Olefin block compositions for heavy weight stretch fabrics

ABSTRACT

Heavy weight stretch fabrics comprising ethylene/α-olefin interpolymer are described. The fabric often has a weight of at least 10 ounces per square yard measured according to ASTM 3776 and has a stretch of at least 10 percent measured according to ASTM D3107. These fabrics exhibit excellent chemical, resistance (for example chlorine or caustic resistance) and durability, that is they retain their shape and feel over repeated exposure to processing conditions, such as stone-washing, dye-stripping, PET-dyeing and the like, and industrial laundry conditions.

CROSS-REFERENCE TO RELATED APPLICATIONS

For purposes of United States patent practice, the contents of U.S. Provisional Application No. 60/868,026 filed on Nov. 30, 2006, PCT Application No. PCT/US2005/008917 (Dow 63558D), filed on Mar. 17, 2005, which in turn claims priority to U.S. Provisional Application No. 60/553,906 and PCT Application No. PCT/US2006/09405, filed on May 24, 2006 are herein incorporated by reference in their entirety.

FIELD OF THE INVENTION

This invention relates to heavy weight fabrics comprised of elastic fibers made from ethylene/α-olefin interpolymer and blends thereof.

BACKGROUND OF THE INVENTION

The current polyurethane based elastomeric fibers (spandex) provide acceptable stretch for some applications but unfortunately are not resistant to many textile processing chemicals and do not stand up well to industrial laundering conditions. They are also often difficult to incorporate into heavy bottom weight fabrics like denim.

To be used in durable fabrics, the fibers making up the fabric have to be, inter alia, stable during dyeing and heat setting processes. For an elastic polyolefin fiber to be stable under dyeing and heat-setting conditions, it is often crosslinked by one or more of a number of different methods, e.g., e-beam or UV irradiation, silane or azide treatment peroxide, etc., some methods better than others for fibers of a particular composition. For example, polyolefin fibers that are irradiated under an inert atmosphere (as opposed to irradiated under air) tend to be highly stable during dyeing processes (that is, the fibers do not melt or fuse together). The addition of a mixture of hindered phenol and hindered amine stabilizers usually further stabilized such fibers at heat setting conditions (200-210° C.).

Lycra®, a segmented polyurethane elastic material manufactured by E. I. du Pont de Nemours Company, is currently used in various durable stretch fabrics. Lycra, however, is not stable at the typical high heat-setting temperatures (200-210° C.) used for polyethylene terephthalate (PET) fiber. Moreover and similar to ordinary uncrosslinked polyolefin-based elastic materials, Lycra fabrics tend to lose their integrity, shape and elastic properties when subjected to elevated service temperatures such as those encountered in washing, drying and ironing. As such, Lycra® cannot be easily used in co-knitting applications with high temperature fibers such as polyester fibers.

Thus, there is a continuing need for heavy weight stretch fabrics which are resistant to many textile processing chemicals and are capable of surviving industrial laundering conditions including chemical and heat treatment.

SUMMARY OF THE INVENTION

Provided herein are heavy weight fabrics comprising fibers comprised of ethylene/α-olefin interpolymer. The fabrics include heavy weight stretch fabrics which are resistant to many textile processing chemicals and are capable of surviving industrial laundering conditions including chemical and heat treatment. The fabrics have one or more of the following properties: dimensional stability, improved ratio of stretch to growth, chemical and heat resistance and industrial laundering durability. In one aspect, the fabrics often weigh at least 6, preferably at least 8, more preferably at least 10 ounces per square yard and have a stretch of at least about 10% or more. Advantageously, heavyweight fabrics may be made that may be bi-stretch, i.e., stretchable in two directions. i.e., the warp and weft directions.

In another aspect, the fabrics provided herein have high temperature tolerance that enables the fabric to have better dimensional stability. The ethylene/α-olefin interpolymer fibers used in the fabrics often have higher shrinkage force at fabric finishing temperatures (50-90° C.). This allows the inventive fabrics to shrink more during the finishing step and therefore have higher stretch and weight compared to conventional fabrics prepared from standard crosslinked, homogeneously branched ethylene polymers (e.g., XLA™ available from The Dow Chemical Company). In addition, the use of ethylene/α-olefin interpolymer also facilitates processing in that the spinning equipment is kept free of residue that sometimes deposits when using conventional branched ethylene polymers ormixtures thereof.

The fabrics provided herein comprise: an ethylene/α-olefin interpolymer, wherein the ethylene/α-olefin interpolymer has one or more of the following characteristics:

(1) an average block index greater than zero and up to about 1.0 and a molecular weight distribution, Mw/Mn, greater than about 1.3; or

(2) at least one molecular fraction which elutes between 40° C. and 130° C. when fractionated using TREF, characterized in that the fraction has a block index of at least 0.5 and up to about 1; or

(3) an Mw/Mn from about 1.7 to about 3.5, at least one melting point, Tm, in degrees Celsius, and a density, d, in grams/cubic centimeter wherein the numerical values of Tm and d correspond to the relationship:

T _(m)>−2002.9−4538.5(d)−2422.2(d)²; or

(4) an Mw/Mn from about 1.7 to about 3.5, and is characterized by a heat of fusion, ΔH in J/g, and a delta quantity, ΔT, in degrees Celsius defined as the temperature difference between the tallest DSC peak and the tallest CRYSTAF peak, wherein the numerical values of ΔT and ΔH have the following relationships:

ΔT>−0.1299(ΔH)+62.81 for ΔH greater than zero and up to 130 J/g,

ΔT≧48° C. for ΔH greater than 130 J/g,

wherein the CRYSTAF peak is determined using at least 5 percent of the cumulative polymer, and if less than 5 percent of the polymer has an identifiable CRYSTAF peak, then the CRYSTAF temperature is 30° C.; or

(5) an elastic recovery, Re, in percent at 300 percent strain and 1 cycle measured with a compression-molded film of the ethylene/α-olefin interpolymer, and has a density, d, in grams/cubic centimeter, wherein the numerical values of Re and d satisfy the following relationship when ethylene/α-olefin interpolymer is substantially free of a cross-linked phase:

Re>1481−1629(d); or

(6) a molecular fraction which elutes between 40° C. and 130° C. when fractionated using TREF, characterized in that the fraction has a molar comonomer content of at least 5 percent higher than that of a comparable random ethylene interpolymer fraction eluting D between the same temperatures, wherein said comparable random ethylene interpolymer has the same comonomer(s) and has a melt index, density, and molar comonomer content (based on the whole polymer) within 10 percent of that of the ethylene/α-olefin interpolymer; or

(7) a storage modulus at 25° C., G′(25° C.), and a storage modulus at 100° C. G′(100° C.), wherein the ratio of G′(25° C.) to G′(100° C.) is in the range of about 1:1 to about 9:1.

The ethylene/α-olefin interpolymer characteristics (1) through (7) above are given with respect to the ethylene/α-olefin interpolymer before any significant crosslinking, i.e., before crosslinking. The ethylene/α-olefin interpolymers useful in the present invention may or may not be crosslinked depending upon the desired properties. By using characteristics (1) through (7) as measured before crosslinking is not meant to suggest that the interpolymer is required or not required to be crosslinked—only that the characteristic is measured with respect to the interpolymer without significant crosslinking. Crosslinking may or may not change each of these properties depending upon the specific polymer and degree of crosslinking.

The fabric typically weighs at least 10 ounces per square yard measured according to ASTM 3776 and have a stretch of at least 10 percent measured according to ASTM D3107.

Typically, the ethylene/α-olefin interpolymer in the fabric provided herein is in form of an elastic fiber.

In one aspect the fabrics provided herein ca withstand the textile processes of mercerization, bleaching, wrinkle and/or flame resistant finishes. In other aspect, the fabrics are also able to withstand multiple high temperature and high pH such as often encountered in, for example, industrial launderings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the melting point/density relationship for the inventive polymers (represented by diamonds) as compared to traditional random copolymers (represented by circles) and Ziegler-Natta copolymers (represented by triangles).

FIG. 2 shows plots of delta DSC-CRYSTAF as a function of DSC Melt Enthalpy for various polymers. The diamonds represent random ethylene/octene copolymers; the squares represent polymer examples 1-4; the triangles represent polymer examples 5-9; and the circles represent polymer examples 10-19. The “X” symbols represent polymer examples A*-F*.

FIG. 3 shows the effect of density on elastic recovery for unoriented films made from inventive interpolymers (represented by the squares and circles) and traditional copolymers (represented by the triangles which are various Dow AFFINITY® polymers). The squares represent inventive ethylene/butene copolymers; and the circles represent inventive ethylene/octene copolymers.

FIG. 4 is a plot of octene content of TREF fractionated ethylene/1-octene copolymer fractions versus TREF elution temperature of the fraction for the polymer of Example 5 (represented by the circles) and comparative polymers E and F (represented by the “X” symbols). The diamonds represent traditional random ethylene/octene copolymers.

FIG. 5 is a plot of octene content of TREF fractionated ethylene/1-octene copolymer fractions versus TREF elution temperature of the fraction for the polymer of Example 5 (curve 1) and for comparative F (curve 2). The squares represent Example F*; and the triangles represent Example 5.

FIG. 6 is a graph of the log of storage modulus as a function of temperature for comparative ethylene/1-octene copolymer (curve 2) and propylene/ethylene-copolymer (curve 3) and for two ethylene/1-octene block copolymers of the invention made with differing quantities of chain shuttling agent (curves 1).

FIG. 7 shows a plot of TMA (1 mm) versus flex modulus for some inventive polymers (represented by the diamonds), as compared to some known polymers. The triangles represent various Dow VERSIFY® polymers; the circles represent various random ethylene/styrene copolymers; and the squares represent various Dow AFFINITY® polymers.

FIG. 8 shows a plot of e-beam radiation versus percent crosslinking for an olefin block copolymer.

DETAILED DESCRIPTION OF THE INVENTION General Definitions

As used herein an “elastic” material is typically characterized as elastic (or as having stretch) if it has a high percent elastic recovery (that is, a low percent permanent set) after application of a biasing force. In certain embodiments, elastic materials are characterized by a combination of three important properties, that is, (i) a low stress or load at strain, (ii) a low percent stress or load relaxation, and (iii) a low percent permanent set. In other words there should be (i) a low stress or load requirement to stretch the material, (ii) zero or low relaxing of the stress or unloading once the material is stretched, and (iii) complete or high recovery to original dimensions after the stretching, biasing or straining is discontinued.

The term “survive” when used in reference to the fabric or article “surviving” a particular treatment means that the fabric exhibits growth of less than a stated percent in both the warp and weft direction after the particular treatment has been conducted. Typically, the stated amount is less than about 25, preferably less than about 25, preferably less than about 15, preferably less than about 10, or most preferably less than about 8%.

The term “growth” refers to residual elongation, or the amount the fabric lengthens after applying a load over a given length of time and allowing recovery, expressed as a percentage of the initial fabric dimension. Growth can be determined using ASTM D3107. Typically, the growth of the fabrics of the present invention is less than about 25, preferably less than about 20, preferably less than about 15, preferably less than about 10, or most preferably less than about 8%.

The term “treatment” includes any process such as chemical or heat treatment, laundering, or Finishing steps. In one aspect treatment includes one or more of a) exposure to a 10% by weight sodium hypochlorite solution for a period of at least 90 minutes at a temperature of at least 140° F.; b) exposure to a 5% by weight permanganate solution for a period of at least 90 minutes at a temperature of at least 140° F.; c) 50 cycles of industrial laundering at temperatures of at least 65° C. d) 20 cycles of drycleaning with perchloroethylene using AATCC test method 158; or e) mercerization under caustic conditions (28-33 Baum or about 20% NaOH or more) at temperatures of at least about 60° C. for 60 seconds or longer. The fabrics of the present invention may be capable of surviving two or more of the aforementioned treatments. This means that a piece of the fabric may be capable of surviving, for example, treatment a) and a separate piece of the same fabric may be capable of surviving treatment b), c), d), or e). It does not necessarily mean that the same piece of fabric will survive, for example, undergoing treatment a) and then undergoing treatment b). However, some fabrics of the invention may do so.

“Polymer” means a polymer compound prepared by polymerizing monomers, whether of the same or a different type. The generic term “polymer” embraces the terms “homopolymer,” “copolymer,” “terpolymer” as well as “interpolymer.”

“Interpolymer” means a polymer prepared by the polymerization of at least two different types of monomers. The generic term “interpolymer” includes the term “copolymer” (which is usually employed to refer to a polymer prepared from two different monomers) as well as the term “terpolymer” (which is usually employed to refer to a polymer prepared from three different types of monomers). It also encompasses polymers made by polymerizing four or more types of monomers.

The term “ethylene/α-olefin interpolymer” generally refers to polymers comprising ethylene and an α-olefin having 3 or more carbon atoms. Preferably, ethylene comprises the majority mole fraction of the whole polymer, i.e., ethylene comprises at least about 50 mole percent of the whole polymer. More preferably ethylene comprises at least about 60 mole percent, at least about 70 mole percent, or at least about 80 mole percent, with the substantial remainder of the whole polymer comprising at least one other comonomer that is preferably an α-olefin having 3 or more carbon atoms. For many ethylene/octene copolymers, the preferred composition comprises an ethylene content greater than about 80 mole percent of the whole polymer and an octene content of from about 10 to about 15, preferably from about 15 to about 20 mole percent of the whole polymer. In some embodiments, the ethylene α-olefin interpolymers do not include those produced in low yields or in a minor amount or as a by-product of a chemical process. While the ethylene/α-olefin interpolymers can be blended with one or more polymers, the as-produced ethylene/α-olefin interpolymers are substantially pure and often comprise a major component of the reaction product of a polymerization process.

The ethylene/α-olefin interpolymers comprise ethylene and one or more copolymerizable α-olefin comonomers in polymerized form, characterized by multiple blocks or segments of two or more polymerized monomer units differing in chemical or physical properties. That is, the ethylene/α-olefin interpolymers are block interpolymers, preferably multi-block interpolymers or copolymers. The terms “interpolymer” and copolymer” are used interchangeably herein. In some embodiments, the multi-block copolymer can be represented by the following formula:

(AB)_(n)

where n is at least 1, preferably an integer greater than 1, such as 2, 3, 4, 5, 10, 15, 20, 30, 40, 50, 60, 70, 80, 90, 100, or higher, “A” represents a hard block or segment and “B” represents a soft block or segment. Preferably, As and Bs are linked in a substantially linear fashion, as opposed to a substantially branched or substantially star-shaped fashion. In other embodiments, A blocks and B blocks are randomly distributed along the polymer chain. In other words, the block copolymers usually do not have a structure as follows.

AAA-AA-BBB-BB

In still other embodiments, the block copolymers do not usually have a third type of block, which comprises different comonomer(s). In yet other embodiments, each of block A and block B has monomers or comonomers substantially randomly distributed within the block. In other words, neither block A nor block B comprises two or more sub-segments (or sub-blocks) of distinct composition, such as a tip segment, which has a substantially different composition than the rest of the block.

The multi-block polymers typically comprise various amounts of “hard” and “soft” segments. “Hard” segments refer to blocks of polymerized units in which ethylene is present in an amount greater than about 95 weight percent, and preferably greater than about 98 weight percent based on the weight of the polymer. In other words, the comonomer content (content of monomers other than ethylene) in the hard segments is less than about 5 weight percent and preferably less than about 2 weight percent based on the weight of the polymer. In some embodiments, the hard segments comprises all or substantially all ethylene. “Soft” segments, on the other hand, refer to blocks of polymerized units in which the comonomer content (content of monomers other than ethylene) is greater than about 5 weight percent, preferably greater than about 8 weight percent, greater than about 10 weight percent, or greater than about 15 weight percent based on the weight of the polymer. In some embodiments, the comonomer content in the soft segments can be greater than about 20 weight percent, greater than about 25 weight percent, greater than about 30 weight percent, greater than about 35 weight percent, greater than about 40 weight percent, greater than about 45 weight percent, greater than about 50 weight percent, or greater than about 60 weight percent.

The soft segments can often be present in a block interpolymer from about 1 weight percent to about 99 weight percent of the total weight of the block interpolymer, preferably from about 5 weight percent to about 95 weight percent, from about 10 weight percent to about 90 weight percent, from about 15 weight percent to about 85 weight percent, from about 20 weight percent to about 80 weight percent, from about 25 weight percent to about 75 weight percent, from about 30 weight percent to about 70 weight percent, from about 35 weight percent to about 65 weight percent, from about 40 weight percent to about 60 weight percent, or from about 45 weight percent to about 55 weight percent of the total weight of the block interpolymer. Conversely, the hard segments can be present in similar ranges. The soft segment weight percentage and the hard segment weight percentage can be calculated based on data obtained from DSC or NMR. Such methods and calculations are disclosed in a concurrently filed U.S. patent application Ser. No. 11/376,835, Attorney Docket No. 385063-999558, entitled “Ethylene/α-Olefin Block Interpolymers”, filed on Mar. 15, 2006, in the name of Colin L. P. Shan, Lonnie Hazlitt, et. al. and assigned to Dow Global Technologies Inc., the disclosure of which is incorporated by reference herein in its entirety.

The term “crystalline” if employed, refers to a polymer that possesses a first order transition or crystalline melting point (Tm) as determined by differential scanning calorimetry (DSC) or equivalent technique. The term may be used interchangeably with the term “semicrystalline”. The term “amorphous” refers to a polymer lacking a crystalline melting point as determined by differential scanning calorimetry (DSC) or equivalent technique.

The term “multi-block copolymer” or “segmented copolymer” refers to a polymer comprising two or more chemically distinct regions or segments (referred to as “blocks”) preferably joined in a linear manner, that is, a polymer comprising chemically differentiated units which are joined end-to-end with respect to polymerized ethylenic functionality, rather than in pendent or grafted fashion. In a preferred embodiment, the blocks differ in the amount or type of comonomer incorporated therein, the density, the amount of crystallinity the crystallite size attributable to a polymer of such composition, the type or degree of tacticity (isotactic or syndiotactic), regio-regularity or regio-irregularity, the amount of branching, including long chain branching or hyper-branching, the homogeneity, or any other chemical or physical property. The multi-block copolymers are characterized by unique distributions of both polydispersity index (PDI or Mw/Mn), block length distribution, and for block number distribution due to the unique process making of the copolymers. More specifically, when produced in a continuous process, the polymers desirably possess PDI from 1.7 to 2.9, preferably from 1.8 to 2.5, more preferably from 1.8 to 2.2, and most preferably from 1.8 to 2.1. When produced in a batch or semi-batch process, the polymers possess PDI from 1.0 to 2.9, preferably from 1.3 to 2.5, more preferably from 1.4 to 2.0, and most preferably from 1.4 to 1.8.

In the following description, all numbers disclosed herein are approximate values, regardless whether the word “about” or “approximate” is used in connection therewith. They may vary by 1 percent, 2 percent, 5 percent, or, sometimes, 10 to 20 percent. Whenever a numerical range with a lower limit, R^(L) and an upper limit, R^(U), is disclosed, any number falling within the range is specifically disclosed. In particular, the following numbers within the range are specifically disclosed: R=R^(L)+k*(R^(U)−R^(L)), wherein k is a variable ranging from 1 percent to 100 percent with a 1 percent increment, i.e., k is 1 percent, 2 percent, 3 percent-4 percent, 5 percent, . . . , 50 percent, 51 percent, 52 percent, . . . , 95 percent, 96 percent, 97 percent, 98 percent, 99 percent, or 100 percent. Moreover, any numerical range defined by two R numbers as defined in the above is also specifically disclosed.

Ethylene/α-Olefin Interpolymers

The ethylene/α-olefin interpolymers used in embodiments of the invention (also referred to as “inventive interpolymer” or “inventive polymer”) comprise ethylene and one or more copolymerizable α-olefin comonomers in polymerized form, characterized by multiple blocks or segments of two or more polymerized monomer units differing in chemical or physical properties (block interpolymer), preferably a multi-block copolymer. The ethylene/α-olefin interpolymers are characterized by one or more of the aspects described as follows.

In one aspect, the ethylene/α-olefin interpolymers used in embodiments of the invention have a M_(w)/M_(n) from about 1.7 to about 3.5 and at least one melting point, T_(m), in degrees Celsius and density, d, in grams/cubic centimeter, wherein the numerical values of the variables correspond to the relationship:

T _(m)>−2002.9+4538.5(d)−2422.2(d)², and preferably

T _(m)≧−6288.1+13141(d)−6720.3(d)², and more preferably

T _(m)≧858.91−1825.3(d)+1112.8(d)².

Such melting point/density relationship is illustrated in FIG. 1. Unlike the traditional random copolymers of ethylene/α-olefins whose melting points decrease with decreasing densities, the inventive interpolymers (represented by diamonds) exhibit melting points substantially independent of the density, particularly when density is between about 0.87 g/cc to about 0.95 glee. For example, the melting point of such polymers are in the range of about 110° C. to about 130° C. when density ranges from 0.875 g/cc to about 0.945 g/cc. In some embodiments, the melting point of such polymers are in the range of about 115° C. to about 125° C. when density ranges from 0.875 glee to about 0.945 g/cc.

In another aspect, the ethylene/α-olefin interpolymers comprise, in polymerized form, ethylene and one or more α-olefins and are characterized by a ΔT, in degree Celsius, defined as the temperature for the tallest Differential Scanning Calorimetry (“DSC”) peak minus the temperature for the tallest Crystallization Analysis Fractionation (“CRYSTAF”) peak and a heat of fusion in J/g, ΔH and ΔT and ΔH satisfy the following relationships:

ΔT>−0.1299(ΔH)+62.81, and preferably

ΔT≧−0.1299(ΔL)+64.38, and more preferably

ΔT≧−0.1299(ΔH)+65.95,

for ΔH up to 130 J/g. Moreover, ΔT is equal to or greater than 48° C. for ΔX greater than 130 J/g. The CRYSTAL peak is determined using at least 5 percent of the cumulative polymer (that is, the peak must represent at least 5 percent of the cumulative polymer), and if less than 5 percent of the polymer has an identifiable CRYSTAF peak then the CRYSTAF temperature is 30° C., and ΔH is the numerical value of the heat of fusion in J/g. More preferably, the highest CRYSTAF peak contains at least 10 percent of the cumulative polymer. FIG. 2 shows plotted data for inventive polymers as well as comparative examples. Integrated peak areas and peak temperatures are calculated by the computerized drawing program supplied by the instrument maker. The diagonal line shown for the random ethylene octene comparative polymers corresponds to the equation ΔT=+0.1299 (ΔH)+62.81.

In yet another aspect, the ethylene α-olefin interpolymers have a molecular fraction which elutes between 40° C. and 130° C. when fractionated using Temperature Rising Elution Fractionation (“TREF”), characterized in that said fraction has a molar comonomer content higher preferably at least 5 percent higher, more preferably at least 10 percent higher, than that of a comparable random ethylene interpolymer fraction eluting between the same temperatures, wherein the comparable random ethylene interpolymer contains the same comonomer(s), and has a melt index, density, and molar comonomer content (based on the whole polymer) within 10 percent of that of the block interpolymer. Preferably, the Mw/Mn of the comparable interpolymer is also within 10 percent of that of the block interpolymer and/or the comparable interpolymer has a total comonomer content within 10 weight percent of that of the block interpolymer.

In still another aspect, the ethylene/α-olefin interpolymers are characterized by/an elastic recovery, Re, in percent at 300 percent strain and 1 cycle measured on a compression-molded film of an ethylene/α-olefin interpolymer and has a density d, in grams/cubic centimeter, wherein the numerical values of Re and d satisfy the following relationship when ethylene/α-olefin interpolymer is substantially free of a cross-linked phase:

Re>1481−1629(d); and preferably

Re≧1491−1629(d) and more preferably

Re≧1501−1629(d); and even more preferably

Re≧1511−1629(d),

FIG. 3 shows the effect of density on elastic recovery for unoriented films made from certain inventive interpolymers and traditional random copolymers. For the same density, the inventive interpolymers have substantially higher elastic recoveries.

In some embodiments, the ethylene/α-olefin interpolymers have a tensile strength above 10 MPa, preferably a tensile strength≧11 MPa more preferably a tensile strength≧13 MPa and/for an elongation at break of at least 600 percent, more preferably at least 700 percent, highly preferably at least 800 percent, and most highly preferably at least 900 percent at a crosshead separation rate of 11 cm/minute.

In other embodiments, the ethylene/α-olefin interpolymers have (1) a storage modulus ratio, G′(25° C.)/G′(100° C.), of from 1 to 50, preferably from 1 to 20, more preferably from 1 to 10: and/or (2) a 70° C. compression set of less than 80 percent, preferably less than 70 percent, especially less than 60 percent, less than 50 percent, or less than 40 percent, down to a compression set of 0 percent.

In still other embodiments, the ethylene/α-olefin interpolymers have a 70° C. compression set of less than 80 percent, less than 70 percent, less than 60 percent, or less than 50 percent. Preferably, the 70° C. compression set of the interpolymers is less than 40 percent, less than 30 percent, less than 20 percent, and may go down to about 0 percent.

In some embodiments, the ethylene/α-olefin interpolymers have a heat of fusion of less than 85 J/g and/or a pellet blocking strength of equal to or less than 100 pounds/foot² (4800 Pa), preferably equal to or less than 50 lbs/ft² ('400 Pa), especially equal to or less than 5 lbs/ft² (240 Pa), and as low as 0 lbs/ft² (0 Pa).

In other embodiments, the ethylene/α-olefin interpolymers comprise, in polymerized form, at least 50 mole percent ethylene and have a 70° C. compression set of less than 80 percent, preferably less than 70 percent or less than 60 percent, most preferably less than 40 to 50 percent and down to close zero percent.

In some embodiments, the multi-block copolymers possess a PDI fitting a Schultz-Flory distribution rather than a Poisson distribution. The copolymers are further characterized as having both a polydisperse block distribution and a polydisperse distribution of block sizes and possessing a most probable distribution of block lengths. Preferred multi-block copolymers are those containing 4 or more blocks or segments including terminal blocks. More preferably, the copolymers include at least 5, 10 or 20 blocks or segments including terminal blocks.

Comonomer content may be measured using any suitable technique, with techniques based on nuclear magnetic resonance (“NMR”) spectroscopy preferred. Moreover, for polymers or blends of polymers having relatively broad TREE curves, the polymer desirably is first fractionated using TREF into fractions each having an eluted temperature range of 10° C. or less. That is, each eluted fraction has a collection temperature window of 10° C. or less. Using this technique, said block interpolymers have at least one such fraction having a higher molar comonomer content than a corresponding fraction of the comparable interpolymer.

In another aspect, the inventive polymer is an olefin interpolymer, preferably comprising ethylene and one or more copolymerizable comonomers in polymerized form, characterized by multiple blocks (i.e., at least two blocks) or segments of two or more polymerized monomer units differing in chemical or physical properties (blocked interpolymer), most preferably a multi-block copolymer, said block interpolymer having a peak (but not just a molecular fraction) which elutes between 40° C. and 130° C. (but without collecting and/or isolating individual fractions), characterized in that said peak, has a comonomer content estimated by in infrared spectroscopy when expanded using a full width/half maximum (FWHM) area calculation, has an average molar comonomer content higher, preferably at least 5 percent higher, more preferably at least 10 percent higher, than that of a comparable random ethylene interpolymer peak at the same elution temperature and expanded using a full width/half maximum (FWHM) area calculation, wherein said comparable random ethylene interpolymer has the same comonomer(s) and has a melt index, density, and molar comonomer content (based on the whole polymer) within 10 percent of that of the blocked interpolymer. Preferably, the Mw/Mn of the comparable interpolymer is also within 10 percent of that of the blocked interpolymer and/or the comparable interpolymer has a total comonomer content within 10 weight percent of that of the blocked interpolymer. The full width/half maximum (FWHM) calculation is based on the ratio of methyl to methylene response area [CH₃/Cl₂] from the ATREF infra-red detector, wherein the tallest (highest) peak is identified from the base line, and then the FWHM area is determined. For a distribution measured using an ATREF peak, the FWHM area is defined as the area under the curve between T₁ and T₂, where T, and f₂ are points determined, to the left and right of the ATREF peak, by dividing the peak height by two, and then drawing a line horizontal to the base line, that intersects the left and right portions of the ATREF curve. A calibration curve for comonomer content is made using random ethylene/α-olefin copolymers, plotting comonomer content from N MR versus FWHM area ratio of the TREF peak. For this infrared method, the calibration curve is generated for the same comonomer type of interest. The comonomer content of TREE peak of the inventive polymer can be determined by referencing this calibration curve using its FWHM methyl:methylene area ratio [CH₃/CH₂] of the TREE peak.

Comonomer content may be measured using any suitable technique, with techniques based on nuclear magnetic resonance (NNMR) spectroscopy preferred. Using this technique, said blocked interpolymers has higher molar comonomer content than a corresponding comparable interpolymer.

Preferably, for interpolymers of ethylene and 1-octene, the block interpolymer has a comonomer content of the TREF fraction eluting between 40 and 130° C. greater than or equal to the quantity (−0.2013) T+20.07, more preferably greater than or equal to the quantity (−0.2013) T+21.07, where T is the numerical value of the peak elution temperature of the TREF 3) fraction being compared, measured in ° C.

FIG. 4 graphically depicts an embodiment of the block interpolymers of ethylene and 1-octene where a plot of the comonomer content versus TREE elution temperature for several comparable ethylene/1-octene interpolymers (random copolymers) are fit to a line representing (−02013) T 20.07 (solid line). The line for the equation (−0.2013)T+21.07 is depicted by a dotted line. Also depicted are the comonomer contents for fractions of several block ethylene/1-octene interpolymers of the invention (multi-block copolymers). All of the block interpolymer fractions have significantly higher 1-octene content than either line at equivalent elution temperatures. This result is characteristic of the inventive interpolymer and is believed to be due to the presence of differentiated blocks within the polymer chains, having both crystalline and amorphous nature.

FIG. 5 graphically displays the TREE curve and comonomer contents of polymer fractions for Example 5 and comparative F discussed below. The peak eluting from 40 to 130° C., preferably from 60° C. to 95° C. for both polymers is fractionated into three parts, each part eluting over a temperature range of less than 10° C. Actual data for Example 5 is represented b by triangles. The skilled artisan can appreciate that an appropriate calibration curve may be constructed for interpolymers containing different comonomers and a line used as a comparison fitted to the TREE values obtained from comparative interpolymers of the same monomers, preferably random copolymers made using a metallocene or other homogeneous catalyst composition. Inventive interpolymers are characterized by a molar comonomer content greater than the value determined from the calibration curve at the same TREF elution temperature, preferably at least 5 percent greater, more preferably at least 10 percent greater.

In addition to the above aspects and properties described herein, the inventive polymers can be characterized by one or more additional characteristics. In one aspect, the inventive polymer is an olefin interpolymer, preferably comprising ethylene and one or more copolymerizable comonomers in polymerized form, characterized by multiple blocks or segments of two or more polymerized monomer units differing in chemical or physical properties (blocked interpolymer), most preferably a multi-block copolymer, said block interpolymer having a molecular fraction which elutes between 40° C. and 130° C., when fractionated using TREE increments, characterized in that said fraction has a molar comonomer content higher, preferably at least 5 percent higher, more preferably at least 10, 15, 20 or 25 percent higher, than that of a comparable random ethylene interpolymer fraction eluting between the same temperatures, wherein said comparable random ethylene interpolymer comprises the same comonomer(s), preferably it is the same comonomer(s), and a melt index, density, and molar comonomer content (based on the whole polymer) within 10 percent of that of the blocked interpolymer. Preferably, the Mw/Mn of the comparable interpolymer is also within 10 percent of that of the blocked interpolymer and, or the comparable interpolymer has a total comonomer content within 10 weight percent of that of the blocked interpolymer.

Preferably, the above interpolymers are interpolymers of ethylene and at least one α-olefin, especially those interpolymers having a whole polymer density from about 0.855 to about 0.935 g/m³, and more especially for polymers having more than about 1 mole percent comonomer, the blocked interpolymer has a comonomer content of the TREF fraction eluting between 40 and 130° C. greater than or equal to the quantity (−0.1356)T+13.89, more preferably greater than or equal to the quantity (−0.1356)T+14.93, and most preferably greater than or equal to the quantity (−0.2013)T+21.07, where T is the numerical value of the peak ATREF elution temperature of the TREF fraction being compared, measured in ° C.

Preferably, for the above interpolymers of ethylene and at least one alpha-olefin especially those interpolymers having a whole polymer density from about 0.855 to about 0.935 g/cm³, and more especially for polymers having more than about 1 mole percent comonomer, the blocked interpolymer has a comonomer content of the TREF fraction eluting between 40 and 130° C. greater than or equal to the quantity (−0.2013)T+20.07, more preferably greater than or equal to the quantity (−0.2013)T+21.07, where T is the numerical value of the peak elution temperature of the TREF fraction being compared, measured in ° C.

In still another aspect, the inventive polymer is an olefin interpolymer, preferably comprising ethylene and one or more copolymerizable comonomers in polymerized form, characterized by multiple blocks or segments of two or more polymerized monomer units differing in chemical or physical properties (blocked interpolymer), most preferably a multi-block copolymer, said block interpolymer having a molecular fraction which elutes between 40° C. and 130° C., when fractionated using TREF increments, characterized in that every fraction having a comonomer content of at least about 6 mole percent, has a melting point greater than about 100° C. For those fractions having a comonomer content from about 3 mole percent to about 6 mole percent, every fraction has a DSC melting point of about 110° C. or higher. More preferably, said polymer fractions, having at least 1 mole percent comonomer has a DSC melting point that corresponds to the equation:

Tm≧(−5.5926)(mole percent comonomer in the fraction)+135.90.

In yet another aspect, the inventive polymer is an olefin interpolymer, preferably comprising ethylene and one or more copolymerizable comonomers in polymerized form, characterized by multiple blocks or segments of two or more polymerized monomer units differing in chemical or physical properties (blocked interpolymer), most preferably a multi-block copolymer, said block interpolymer having a molecular fraction which elutes between 40° C. and 130° C. when fractionated using TREF increments, characterized in that every fraction that has an ATREF elution temperature greater than or equal to about 76° C., has a melt enthalpy (heat of fusion) as measured by DSC, corresponding to the equation:

Heat of fusion (J/gm)≦(3.1718)(ATREF elution temperature in Celsius)−136.58,

The inventive block interpolymers have a molecular fraction which elutes between 40° C. and 130° C., when fractionated using TREE increments, characterized in that every fraction that has an ATREF elution temperature between 40° C. and less than about 76° C. has a melt enthalpy (heat of fusion) as measured by DSC, corresponding to the equation:

Heat of fusion (J/gm)≦(1.1312)(ATREF elution temperature in Celsius)+22.97.

ATREF Peak Comonomer Composition Measurement by Infra-Red Detector

The comonomer composition of the TREF peak can be measured using an IR4 infra-red detector available from Polymer Char, Valencia, Spain (http://www.polymerchar.com/).

The “composition mode” of the detector is equipped with a measurement sensor (CH₂) and composition sensor (CH₃) that are fixed narrow band infra-red filters in the region of 2800-3000 cm⁻¹, The measurement sensor detects the methylene (CH₂) carbons on the polymer (which directly relates to the polymer concentration in solution) while the composition sensor detects the methyl (CH₃) groups of the polymer. The mathematical ratio of the composition signal (CH₃) divided by the measurement signal (CH₂) is sensitive to the comonomer content of the measured polymer in solution and its response is calibrated with known ethylene alpha-olefin copolymer standards.

The detector when used with an ATREF instrument provides both a concentration (CH₂) and composition (CH₃) signal response of the eluted polymer during the TREF process. A polymer specific calibration can be created by measuring the area ratio of the CH₃ to CH₂ for polymers with known comonomer content (preferably measured by NMR). The comonomer content of an ATREF peak of a polymer can be estimated by applying a the reference calibration of the ratio of the areas for the individual CH₃ and CH₂ response (i.e. area ratio CH₃/CH₂ versus comonomer content).

The area of the peaks can be calculated using a full width/half maximum (FWHM) calculation after applying the appropriate baselines to integrate the individual signal responses from the TREF chromatogram. The full width/half maximum calculation is based on the ratio of methyl to methylene response area [CH₃/CH₂] from the ATREF infra-red detector, wherein the tallest (highest) peak is identified from the base line, and then the FWHM area is determined. For a distribution measured using an ATREF peak, the FWHM area is defined as the area under the curve between T1 and T2, where T1 and T2 are points determined, to the left and right of the ATREF peak, by dividing the peak height by two, and then drawing a line horizontal to the base line, that intersects the left and right portions of the ATREF curve.

The application of infra-red spectroscopy to measure the comonomer content of polymers in this ATREF-infra-red method is, in principle, similar to that of GPC/FTIR systems as described in the following references: Markovich, Ronald P.; Hazlitt, Lonnie G.; Smith, Linley; “Development of gel-permeation chromatography-Fourier transform infrared spectroscopy for characterization of ethylene-based polyolefin copolymers”. Polymeric Materials Science and Engineering (1991), 65, 98-100.; and Deslauriers, P. J.; Rohlfing, D. C.: Shieh, E. T.; “Quantifying short chain branching microstructures in ethylene-1-olefin copolymers using size exclusion chromatography and Fourier transform infrared spectroscopy (SEC-FTIR)”, Polymer (2002), 43, 59-170, both of which are incorporated by reference herein in their entirety.

In other embodiments, the inventive ethylene/α-olefin interpolymer is characterized by an average block index, ABI, which is greater than zero and up to about 1.0 and a molecular weight distribution, M_(w)/M_(n), greater than about 1.3. The average block index, ABI, is the weight average of the block index (“BI”) for each of the polymer fractions obtained in preparative TREF from 20° C. and 110° C. with an increment of 5° C.:

ABI=Σ(w _(i)BI_(i))

where BI_(i) is the block index for the ith fraction of the inventive ethylene/α-olefin interpolymer obtained in preparative TREF, and w_(i) is the weight percentage of the ith fraction.

For each polymer fraction, BI is defined by one of the two following equations (both of which give the same BI value):

${BI} = {{\frac{{1/T_{X}} - {1/T_{XO}}}{{1/T_{A}} - {1/T_{AB}}}\mspace{14mu} {or}\mspace{14mu} {BI}} = \frac{{LnP}_{X} - {LnP}_{XO}}{{LnP}_{A} - {LnP}_{AB}}}$

where T_(X) is the preparative ATREF elution temperature for the ith fraction (preferably expressed in Kelvin), P_(X) is the ethylene mole traction for the ith fraction, which can be measured by NMR or IR as described above. P_(AB) is the ethylene mole fraction of the whole ethylene/α-olefin interpolymer (before fractionation), which also can be measured by NMR or IR. T_(A) and P_(A) are the ATREF elution temperature and the ethylene mole fraction for pure “hard segments” (which refer to the crystalline segments of the interpolymer). As a first order approximation, the T_(A) and P_(A) values are set to those for high density polyethylene homopolymer, if the actual values for the “hard segments” are not available. For calculations performed herein, T_(A) is 372° K, P_(A) is 1.

T_(AB) is the ATREF temperature for a random copolymer of the same composition and having an ethylene mole fraction of P_(AB). T_(AB) can be calculated from the following equation:

Ln P _(AB) =α/T _(AB)β

where α and β are two constants which can be determined by calibration using a number of known random ethylene copolymers. It should be noted that α and β may vary from instrument to instrument. Moreover, one would need to create their own calibration curve with the polymer composition of interest and also in a similar molecular weight range as the fractions. There is a slight molecular weight effect. If the calibration curve is obtained from similar molecular weight ranges, such effect would be essentially negligible. In some embodiments, random ethylene copolymers satisfy the following relationship:

Ln P=−237.83/T _(ATREF)+0.639

T_(XO) is the ATREF temperature for a random copolymer of the same composition and having an ethylene mole fraction of P_(X). T_(XO) can be calculated from Ln P_(X)=α/T_(XO)+β. Conversely, P_(XO) is the ethylene mole fraction for a random copolymer of the same composition and having an ATREF temperature of T_(X), which can be calculated from Ln P_(XO)=α/T_(X)+β.

Once the block index (BI) for each preparative TREF fraction is obtained, the weight average block index, ABI, for the whole polymer can be calculated. In some embodiments, ABI is greater than zero but less than about 0.3 or from about 0.1 to about 0.3. In other embodiments. ABI is greater than about 0.3 and up to about 1.0. Preferably, ABI should be in the range of from about 0.4 to about 0.7, from about 0.5 to about 0.7, or from about 0.6 to about 0.9. In some embodiments, ABI is in the range of from about 0.3 to about 0.9, from about 0.3 to about 0.8, or from about 0.3 to about 0.7, from about 0.3 to about 0.6, from about 0.3 to about 0.5, or from about 0.3 to about 0.4. In other embodiments, ABI is in the range of from about 0.4 to about 1.0, from about 0.5 to about 1.0, or from about 0.6 to about 1.0, from about 0.7 to about 1.0, from about 0.8 to about 1.0, or from about 0.9 to about 1.0.

Another characteristic of the inventive ethylene/α-olefin interpolymer is that the inventive ethylene/α-olefin interpolymer comprises at least one polymer fraction which can be obtained by preparative TREF, wherein the fraction has a block index greater than about 0.1 and up to about 1.0 and a molecular weight distribution, M_(w)/M_(n), greater than about 1.3. In some embodiments, the polymer fraction has a block index greater than about 0.6 and up to about 1.0, greater than about 0.7 and up to about 1.0, greater than about 0.8 and up to about 1.0, or greater than about 0.9 and up to about 1.0. In other embodiments, the polymer fraction has a block index grater than about 0.1 and up to about 1.0, greater than about 0.2 and up to about 1.0, greater than about 0.3 and up to about 1.0, greater than about 0.4 and up to about 1.0, or greater than about 0.4 and up to about 1.0. In still other embodiments, the polymer fraction has a block index greater than about 0.1 and up to about 0.5, greater than about 0.2 and up to about 0.5, greater than about 0.3 and up to about 0.5, or greater than about 0.4 and up to about 0.5. In yet other embodiments, the polymer fraction has a block index greater than about 0.2 and up to about 0.9, greater than about 0.3 and up to about 0.8, greater than about 0.4 and up to about 0.7, or greater than about 0.5 and up to about 0.6.

For copolymers of ethylene and an α-olefin, the inventive polymers preferably possess (1) a PDI of at least 1.3, more preferably at least 1.5, at least 1.7, or at least 2.0, and most preferably at least 2.6, up to a maximum value of 5.0, more preferably up to a maximum of 3.5, and especially up to a maximum of 2.7: (2) a heat of fusion of 80 J/g or less; (3) an ethylene content of at least 50 weight percent; (4) a glass transition temperature, T_(g), of less than −25° C., more preferably less than −30° C., and/or (5) one and only one T_(m).

Further, the inventive polymers can have, alone or in combination with any other properties disclosed herein, a storage modulus G′, such that log(G′) is greater than or equal to 400 kPa, preferably greater than or equal to 1.0 MPa, at a temperature of 100° C. Moreover, the inventive polymers possess a relatively flat storage modulus as a function of temperature in the range from 0 to 100° C. (illustrated in FIG. 6) that is characteristic of block copolymers, and heretofore unknown for an olefin copolymer, especially a copolymer of ethylene and one or more C₃₋₈ aliphatic α-olefins. (By the term “relatively flat” in this context is meant that log G′ (in Pascals) decreases by less than one order of magnitude between 50 and 100° C., preferably between 0 and 100° C.).

The inventive interpolymers may be further characterized by a thermomechanical analysis penetration depth of 1 mm at a temperature of at least 90° C. as well as a flexural modulus of from 3 kpsi (20 MPa) to 13 kpsi (90 MPa). Alternatively, the inventive interpolymers can have a thermomechanical analysis penetration depth of 1 mm at a temperature of at least 104° C. as well as a flexural modulus of at least 3 kpsi (20 MPa). They may be characterized as having an abrasion resistance (or volume loss) of less than 90 mm³. FIG. 7 shows the TMA (1 mm) versus flex modulus for the inventive polymers, as compared to other known polymers. The inventive polymers have significantly better flexibility-heat resistance balance than the other polymers.

Additionally, the ethylene/α-olefin interpolymers can have a melt index, I₂, from 0.01 to 2000 g/10 minutes, preferably from 0.01 to 1000 g/10 minutes, more preferably from 0.01 to 500 g/10 minutes, ad especially from 0.01 to 100 g/10 minutes. In certain embodiments, the ethylene/α-olefin interpolymers have a melt index, I₂, from 0.01 to 10 g/10 minutes, from 0.5 to 50 to 10 minutes, from 1 to 30 g/10 minutes, from 1 to 6 g/10 minutes or from 0.3 to 10 g/10 minutes. In certain embodiments, the melt index for the ethylene/α-olefin polymers is 1 g/10 minutes, 3 g/10 minutes or 5 g/10 minutes.

The polymers can have molecular weights, M_(w), from 1,000 g/mole to 5,000.000 g/mole, preferably from 1000 g/mole to 1,000,000, more preferably from 10,000 g/mole to 500,000 g/mole, and especially from 10,000 g/mole to 300,000 g/mole. The density of the inventive polymers can be from 0.80 to 0.99 g/cm³ and preferably for ethylene containing polymers from 0.85 g/cm³ to 0.97 g/cm³. In certain embodiments, the density of the ethylene/α-olefin polymers ranges from 0.860 to 0.925 g/cm³ or 0.867 to 0.910 g/cm³.

The process of making the polymers has been disclosed in the following patent applications: U.S. Provisional Application No. 60/553,906, filed Mar. 17, 2004; U.S. Provisional Application No. 60/662,937, filed Mar. 17, 2005; U.S. Provisional Application No. 60/662,939, filed Mar. 17, 2005; U.S. Provisional Application No. 60/566,2938, filed Mar. 17, 2005; PCT Application No. PCT/US2005/008916, filed Mar. 17, 2005; PCT Application No. PCT/US2005/008915, Piled Mar. 17, 2005; and PCT Application No. PCT/US2005/008917, filed Mar. 17, 2005, all of which are incorporated by reference herein it their entirety. For example, one such method comprises contacting ethylene and optionally one or more addition polymerizable monomers other than ethylene under addition polymerization conditions with a catalyst composition comprising:

the admixture or reaction product resulting from combining:

(A) a first olefin polymerization catalyst having a high comonomer incorporation index,

(B) a second olefin polymerization catalyst having a comonomer incorporation index less than 90 percent, preferably less than 50 percent, most preferably less than 5 percent of the comonomer incorporation index of catalyst (A), and

(C) a chain shuttling agent.

Representative catalysts and chain shuttling agent are as follows.

Catalyst (A1) is [N-(2,6-di(1-methylethyl)phenyl)amido)(2-isopropylphenyl)(α-naphthalen-2-diyl(6-pyridin-2-diyl)methane)]hafnium dimethyl, prepared according to the teachings of WO 03/40195, 2003US0204017, USSN 10/429,024, filed May 2, 2003, and WO 04/24740.

Catalyst (A2) is [N-(2,6-di(1-methylethyl)phenyl)amido)(2-methylphenyl)(1,2-phenylene-(6-pyridin-2-diyl)methane)]hafnium dimethyl, prepared according to the teachings of WO 03/40195, 2003US0204017, USSN No. 10/429,024, filed May 2, 2003, and WO 04/24740.

Catalyst (A3) is bis[N,N′″-(2,4,6-tri(methylphenyl)amido)ethylenediamine]hafnium dibenzyl.

Catalyst (A4) is bis((2-oxoyl-3-(dibenzo-1H-pyrrole-1-yl)-5-(methyl)phenyl)-2-phenoxymethyl)cyclohexane-1,2-diyl zirconium (IV) dibenzyl, prepared substantially according to the teachings of US-A-2004/0010103.

Catalyst (B1) is 1,2-bis-(3,5-di-t-butylphenylene)(1-(N-(1-methylethyl)immino)methyl)(2-oxoyl) zirconium dibenzyl

Catalyst (B2) is 1,2-bis-(3,5-di-t-butylphenylene)(1-(N-(2-methylcyclohexyl)-immino)methyl)(2-oxoyl) zirconium dibenzyl

Catalyst (C1) is (t-butylamido)dimethyl(3-N-pyrrolyl-1,2,3,3a,7a-η-inden-1-yl)silanetitanium dimethyl prepared substantially according to the techniques of USP 6,268,444:

Catalyst (C2) is (t-butylamido)di(4-methylphenyl)(2-methyl-1,2,3,3a,7a-η-inden-1-yl)silanetitanium dimethyl prepared substantially according to the teachings of US-A-2003/004286:

Catalyst (C3) is (t-butylamido)di(4-methylphenyl)(2-methyl-1,2,3,3a,8a-η-s-indacen-1-yl)silanetitanium dimethyl prepared substantially according to the teachings of US-A-2003/004286:

Catalyst (D1) is bis(dimethyldisiloxane)(indene-1-yl)zirconium dichloride available from Sigma-Aldrich:

Shuttling Agents The shuttling agents employed include diethylzinc, di(i-butyl)zinc, di(n-hexyl)zinc, triethylaluminum, trioctylaluminum, triethylgallium, i-butylaluminum bis(dimethyl(t-butyl)siloxane), i-butylaluminum bis(di(trimethylsilyl)amide), n-octylaluminum di(pyridine-2-methoxide), bis(n-octadecyl)i-butylaluminum, i-butylaluminum bis(di(n-pentyl)amide), n-octylaluminum bis(2,6-di-t-butylphenoxide, n-octylaluminum di(ethyl (1-naphthyl)amide), ethylaluminum bis(t-butyldimethylsiloxide), ethylaluminum di(bis(trimethylsilyl)amide), ethylaluminum bis(2,3,6,7-dibenzo-1-azacycloheptaneamide), n-octylaluminum bis(2,3,6,7-dibenzo-1-azacycloheptaneamide), n-octylaluminum bis(dimethyl(t-butyl)siloxide, ethylzinc (2,6-diphenylphenoxide), and ethylzinc (t-butoxide).

Preferably, the foregoing process takes the form of a continuous solution process for forming block copolymers, especially multi-block copolymers, preferably linear multi-block copolymers of two or more monomers, more especially ethylene and a C₃₋₂₀ olefin or cycloolefin, and most especially ethylene and a C₄₋₂₀ α-olefin, using multiple catalysts that are incapable of interconversion. That is, the catalysts are chemically distinct. Under continuous solution polymerization conditions, the process is ideally suited for polymerization of mixtures of monomers at high monomer conversions. Under these polymerization conditions, shuttling from the chain shuttling agent to the catalyst becomes advantaged compared to chain growth, and multi-block copolymers, especially linear multi-block copolymers are formed in high efficiency.

The inventive interpolymers may be differentiated from conventional, random copolymers, physical blends of polymers, and block copolymers prepared via sequential monomer addition, fluxional catalysts, anionic or cationic living polymerization techniques. In particular, compared to a random copolymer of the same monomers and monomer content at equivalent crystallinity or modulus, the inventive interpolymers have better (higher) heat resistance as measured by melting point, higher TMA penetration temperature, higher high-temperature tensile strength, and/or higher high-temperature torsion storage modulus as determined by dynamic mechanical analysis. Compared to a random copolymer containing the same monomers and monomer content, the inventive interpolymers have lower compression set, particularly at elevated temperatures, lower stress relaxation, higher creep resistance, higher tear strength, higher blocking resistance, faster setup due to higher crystallization (solidification) temperature, higher recovery (particularly at elevated temperatures), better abrasion resistance, higher retractive force, and better oil and filler acceptance.

The inventive interpolymers also exhibit a unique crystallization and branching distribution relationship. That is, the inventive interpolymers have a relatively large difference between the tallest peak temperature measured using CRYSTAF and DSC as a function of heat of fusion, especially as compared to random copolymers containing the same monomers and monomer level or physical blends of polymers, such as a blend of a high density polymer and a lower density copolymer, at equivalent overall density. It is believed that this unique feature of the inventive interpolymers is due to the unique distribution of the comonomer in blocks within the polymer backbone. In particular, the inventive interpolymers may comprise alternating blocks of differing comonomer content (including homopolymer blocks). The inventive interpolymers may also comprise a distribution in number and/or block size of polymer blocks of differing density or comonomer content, which is a Schultz-Flory type of distribution. In addition, the inventive interpolymers also have a unique peak melting point and crystallization temperature profile that is substantially independent of polymer density, modulus, and morphology. In a preferred embodiment, the microcrystalline order of the polymers demonstrates characteristic spherulites and lamellae that are distinguishable from random or block copolymers, even at PDI values that are less than 1.7, or even less than 1.5, down to less than 1.3.

Moreover, the inventive interpolymers may be prepared using techniques to influence the degree or level of blockiness. That is the amount of comonomer and length of each polymer block or segment can be altered by controlling the ratio and type of catalysts and shuttling agent as well as the temperature of the polymerization, and other polymerization variables. A surprising benefit of this phenomenon is the discovery that as the degree of blockiness is increased, the optical properties, tear strength, and high temperature recovery properties of the resulting polymer are improved. In particular, haze decreases while clarity, tear strength, and high temperature recovery properties increase as the average number of blocks in the polymer increases. By selecting shuttling agents and catalyst combinations having the desired chain transferring ability (high rates of shuttling with low levels of chain termination) other forms of polymer termination are effectively suppressed. Accordingly, little if any β-hydride elimination is observed in the polymerization of ethylene/α-olefin comonomer mixtures according to embodiments of the invention and the resulting crystalline blocks are highly, or substantially completely, linear, possessing little or no long chain branching.

Polymers with highly crystalline chain ends can be selectively prepared in accordance with embodiments of the invention. In elastomer applications, reducing the relative quantity of polymer that terminates with an amorphous block reduces the intermolecular dilutive effect on crystalline regions. This result can be obtained by choosing chain shuttling agents and catalysts having an appropriate response to hydrogen or other chain terminating agents. Specifically, if the catalyst which produces highly crystalline polymer is more susceptible to chain termination (such as by use of hydrogen) than the catalyst responsible for producing the less crystalline polymer segment (such as through higher comonomer incorporation, regio-error, or atactic polymer formation), then the highly crystalline polymer segments will preferentially populate the terminal portions of the polymer. Not only are the resulting terminated groups crystalline, but upon termination, the highly crystalline polymer forming catalyst site is once again available for reinitiation of polymer formation. The initially formed polymer is therefore another highly crystalline polymer segment. Accordingly, both ends of the resulting multi-block copolymer are preferentially highly crystalline.

The ethylene α-olefin interpolymers used in the embodiments of the invention are preferably interpolymers of ethylene with at least one C₃-C₂₀ α-olefin. Copolymers of ethylene and a C₃-C₂₀ α-olefin are especially preferred. The interpolymers may further comprise C₄-C₁₈ diolefin and/or alkenylbenzene. Suitable unsaturated comonomers useful for polymerizing with ethylene include, for example, ethylenically unsaturated monomers, conjugated or nonconjugated dienes, polyenes, alkenylbenzenes, etc. Examples of such comonomers include C₃-C₂₀ α-olefins such as propylene, isobutylene, 1-butene, 1-hexene, 1-pentene, 4-methyl-1-pentene, 1-heptene, 1-octene, 1-nonene, 1-decene, and the like. 1-Butene and 1-octene are especially preferred. Other suitable monomers include styrene, halo- or alkyl-substituted styrenes, vinylbenzocyclobutane, 1,4-hexadiene, 1,7-octadiene, and naphthenics (e.g., cyclopentene, cyclohexene and cyclooctene).

While ethylene/α-olefin interpolymers are preferred polymers, other ethylene/olefin polymers may also be used. Olefins as used herein refer to a family of unsaturated hydrocarbon-based compounds with at least one carbon-carbon double bond. Depending on the selection of catalysts, any olefin may be used in embodiments of the invention. Preferably, suitable olefins are C3-C20 aliphatic and aromatic compounds containing vinylic unsaturation, as well as cyclic compounds, such as cyclobutene, cyclopentene, dicyclopentadiene, and norbornene, including but not limited to, norbornene substituted in the 5 and 6 position with C₁-C₂₀ hydrocarbyl or cyclohydrocarbyl groups. Also included are mixtures of such olefins as well as mixtures of such olefins with C₄-C₄₀ diolefin compounds.

Examples of olefin monomers include, but are not limited to propylene, isobutylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, and 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicosene, 3-methyl-1-butene, 3-methyl-1-pentene, 4-methyl-1-pentene, 4,6-dimethyl-1-heptene, 4-vinylcyclohexene, vinylcyclohexane, norbornadiene, ethylidene norbornene, cyclopentene, cyclohexene, dicyclopentadiene, cyclooctene, C₄-C₄₀ dienes, including but not limited to 1,3-butadiene, 1,3-pentadiene, 1,4-hexadiene, 1,5-hexadiene, 1,7-octadiene, 1,9-decadiene, other C₄-C₄₀ α-olefins, and the like. In certain embodiments, the α-olefin is propylene, 1-butene, 1-pentene, 1-hexene, 1-octene or a combination thereof. Although any hydrocarbon containing a vinyl group potentially may be used in embodiments of the invention, practical issues such as monomer availability, cost, and the ability to conveniently remove unreacted monomer from the resulting polymer may become more problematic as the molecular weight of the monomer becomes too high.

The polymerization processes described herein are well suited for the production of olefin polymers comprising monovinylidene aromatic monomers including styrene, o-methyl styrene, p-methyl styrene, t-butylstyrene, and the like. In particular, interpolymers comprising ethylene and styrene can be prepared by following the teachings herein. Optionally, copolymers comprising ethylene, styrene and a C₃-C₂₀ alpha olefin, optionally comprising a C₄-C₂₀ diene, having improved properties can be prepared.

Suitable non-conjugated diene monomers can be a straight chain, branched chain or cyclic hydrocarbon diene having from 6 to 15 carbon atoms. Examples of suitable non-conjugated dienes include, but are not limited to, straight chain acyclic dienes, such as 1,4-hexadiene, 1,6-octadiene, 1,7-octadiene, 1,9-decadiene, branched chain acyclic dienes, such as 5-methyl-1,4-hexadiene; 3,7-dimethyl-1,6-octadiene; 3,7-dimethyl-1,7-octadiene and mixed isomers of dihydromyricene and dihydroocinene, single ring alicyclic dienes, such as 1,3-cyclopentadiene; 1,4-cyclohexadiene; 1,5-cyclooctadiene and 1,5-cyclododecadiene, and multi-ring alicyclic fused and bridged ring dienes, such as tetrahydroindene, methyl tetrahydroindene, dicyclopentadiene, bicyclo-(2,2,1)-hepta-2,5-diene; alkenyl, alkylidene, cycloalkenyl and cycloalkylidene norbornenes, such as 5-methylene-2-norbornene (MNB); 5-propenyl-2-norbornene, 5-isopropylidene-2-norbornene, 5-(4-cyclopentenyl)-2-norbornene, 5-cyclohexylidene-2-norbornene, 5-vinyl-2-norbornene, and norbornadiene. Of the dienes typically used to prepare EPDMs, the particularly preferred dienes are 1,4-hexadiene (HD), 5-ethylidene-2-norbornene (ENB), 5-vinylidene-2-norbornene (VNB), 5-methylene-2-norbornene (MNB), and dicyclopentadiene (DCPD). The especially preferred dienes are 5-ethylidene-2-norbornene (ENB) and 1,4-hexadiene (HD).

One class of desirable polymers that can be made in accordance with embodiments of the invention are elastomeric interpolymers of ethylene, a C₃-C₂₀ α-olefin, especially propylene, and optionally one or more diene monomers. Preferred α-olefins for use in this embodiment of the present invention are designated by the formula CH₂═CHR*, where R* is a linear or branched alkyl group of from 1 to 12 carbon atoms. Examples of suitable α-olefins include, but are not limited to, propylene, isobutylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, and 1-octene. A particularly preferred α-olefin is propylene. The propylene based polymers are generally referred to in the art as EP or EPDM polymers. Suitable dienes for use in preparing such polymers, especially multi-block EPDM type polymers include conjugated or non-conjugated, straight or branched chain-, cyclic- or polycyclic-dienes comprising from 4 to 20 carbons. Preferred dienes include 1,4-pentadiene, 1,4-hexadiene, 5-ethylidene-2-norbornene, dicyclopentadiene, cyclohexadiene, and 5-butylidene-2-norbornene. A particularly preferred diene is 5-ethylidene-2-norbornene.

Because the diene containing polymers comprise alternating segments or blocks containing greater or lesser quantities of the diene (including none) and α-olefin (including none), the total quantity of diene and α-olefin may be reduced without loss of subsequent polymer properties. That is, because the diene and α-olefin monomers are preferentially incorporated into one type of block of the polymer rather than uniformly or randomly throughout the polymer, they are more efficiently utilized and subsequently the crosslink density of the polymer can be better controlled. Such crosslinkable elastomers and the cured products have advantaged properties, including higher tensile strength and better elastic recovery.

In some embodiments, the inventive interpolymers made with two catalysts incorporating differing, quantities of comonomer have a weight ratio of blocks formed thereby from 95:5 to 5:95. The elastomeric polymers desirably have an ethylene content of from 20 to 90 percent, a diene content of from 0.1 to 10 percent, and an α-olefin content of from 10 to 80 percent, based on the total weight of the polymer. Further preferably, the multi-block elastomeric polymers have an ethylene content of from 60 to 90 percent, a diene content of from 0.1 to 10 percent, and an α-olefin content of from 10 to 40 percent, based on the total weight of the polymer. Preferred polymers are high molecular weight polymers, having a weight average molecular weight (Mw) from 10,000 to about 2,500,000, preferably from 20,000 to 500,000, more preferably (Mw) from 20,000 to 350,000, and a polydispersity less than 3.5, more preferably less than 3.0, and a Mooney viscosity (ML (1+4) 125° C.) from 1 to 250. More preferably, such polymers have an ethylene content from 65 to 75 percent, a diene content from 0 to 6 percent, and an α-olefin content from 20 to 35 percent.

The ethylene/α-olefin interpolymers can be functionalized by incorporating at least one functional group in its polymer structure. Exemplary functional groups may include, for example, ethylenically unsaturated mono- and di-functional carboxylic acids, ethylenically unsaturated mono- and di-functional carboxylic acid anhydrides, salts thereof and esters thereof. Such functional groups may be grafted to an ethylene/α-olefin interpolymer, or it may be copolymerized with ethylene and an optional additional comonomer to form an interpolymer of ethylene, the functional comonomer and optionally other comonomer(s). Means for grafting functional groups onto polyethylene are described for example in U.S. Pat. Nos. 4,762,890, 4,927,888, and 4,950,541, the disclosures of these patents are incorporated herein by reference in their entirety. One particularly useful functional group is malic anhydride.

The amount of the functional group present in the functional interpolymer can vary. The functional group can typically be present in a copolymer-type functionalized interpolymer in an amount of at least about 1.0 weight percent, preferably at least about 5 weight percent, and more preferably at least about 7 weight percent. The functional group will typically be present in a copolymer-type functionalized interpolymer in an amount less than about 40 weight percent, preferably less than about 30 weight percent, and more preferably less than about 25 weight percent.

The Heavy Weight Fabric

The amount of ethylene/α-olefin interpolymer used in the fabric varies depending upon the desired application and properties. Typically, the more interpolymer employed, the more stretch that the fabric will have. In one embodiment, the ethylene/α-olefin interpolymer typically comprises at least about 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or 14 percent by weight up to about 11, 12, 13, 14, 15, 16, or 18 percent by weight of the fabric. Preferably, the ethylene/α-olefin interpolymer comprises from at least about 1 to about 15, preferably from at least about 1 to about 10 percent, more preferably from about 1 to about 3 percent by weight of the fabric. The growth is often such that the growth to stretch ratio is usually less than 0.5, preferably less than 0.4, preferably less than 0.35, preferably less than 0.3, preferably less than 0.25, preferably less than 0.2, preferably less than 0.15, preferably less than 0.1, preferably less than 0.05.

As an alternative to the ethylene/α-olefin interpolymer (or in addition to it) the elastic fiber may comprise a polyolefin blend having an overall melt index (I₂) of less than 2.5 g/10 min before crosslinking with a density in the range of about 0.865 to 0.885 g/cm³. Such a polyolefin blend may comprises a first polyolefin having a density from about 0.855 to about 0.88 g/cm³ and a second polyolefin having a residual crystallinity at 80° C. of greater than 9%. Similarly, the polyolefin blend may have a density from about 0.855 to about 0.88 g/cm³; a residual crystallinity at 80° C. of greater than 9%; or both a density from about 0.855 to about 0.88 g/cm³ and a residual crystallinity at 80° C. of greater than 9%. Thus, in essence, the fabric is comprised of a first, a second, or a first and second polyolefin comprising homogeneously branched polyethylene. However, it has been discovered that occasionally if the fiber does not comprise at least some ethylene/α-olefin interpolymer some processing difficulties may occur such as deposits on the spinning equipment.

The weight of the heavy weight fabric will vary depending upon the desired end use and/or desired properties. The heavy weight fabric provided herein typically has a weight of at least about 10 ounces per square yard measured according to ASTM D3776. In certain embodiments, the heavy weight fabric provided herein has a weight of at least about 10, 10.5, 11, 11.5, 12, 12.5, 13 or even as much as 15 or more ounces per square yard measured according to ASTM D3776. Without being bound to any particular theory, it is believed that the fabric comprising ethylene/α-olefin interpolymer can be weaved in a tighter configuration as compared with many other fabrics such as XLA® due to the unique properties of ethylene/α-olefin interpolymer such as melting point. The resulting fabric can therefore be manufactured to a higher weight. The inventive fabrics often exhibit excellent chemical, resistance (for example chlorine or caustic resistance) and durability, that is they retain their shape and feel over repeated exposure to processing conditions, such as stone-washing, dye-stripping, PET-dyeing and the like, and service conditions, such as washing, drying, etc.

The heavy weight fabric comprising the elastic fiber can be manufactured such that it exhibits a desired amount of stretch. While this varies depending upon the application often it is at least about 5, preferably at least about 8, preferably at least about 9, preferably at least about 10, preferably at least about 11, preferably at least about 12, preferably at least about 13, preferably at least about 14, preferably at least about 18, preferably at least about 20 up to as much as 25 percent or more. Advantageously, the fabric has a good permanent set and thus is capable of returning to a value close to its original dimensions after release of the stretching force as per ASEM D3107.

The heavy weight fabric provided herein is often capable of surviving industrial laundering conditions including chemical and or heat treatment. In certain embodiments, the chemical and/or heat treatment includes exposure to a 10% by weight sodium hypochlorite solution for a period of at least 90 minutes at a temperature of at least 140° F.; exposure to a 5% by weight permanganate solution for a period of at least 90 minutes at a temperature of at least 140° F.; 50 cycles of industrial laundering at temperatures at least about 65° C.; 20 cycles of drycleaning with perchloroethylene; or mercerization. Because of the aforementioned capability, some heavy weight fabrics provided herein may be able to undergo textile processes such as mercerization, bleaching and/or wrinkle and flame resistant finishes without significant growth.

In certain embodiments, the fibers useful herein further comprises a crosslinked elastic fiber. In certain embodiments, the crosslinked elastic fiber is characterized in that the fiber is made from a composition comprising a polyolefin blend having an overall melt index (I₂ less than or equal to 2.5 g, 10 min with an overall density, determined according to ASTM D-792, in the range of 0.865 to 0.885 g/cm³.

In certain embodiments, the fiber used herein further comprises other polymers, for example, random ethylene copolymers such as AFFINITY® or ENGAGE®, traditional polyethylenes such as HDPE, LLDPE, ULDPE, LDPE and propylene-based polymers such as homopolymer PP, random copolymer PP or PP-based plastomers/elastomers, fully hydrogenated styrene block copolymers (also known as catalytically modified polymers) or a combination thereof. The ethylene polymers include the homogeneously branched and the substantially linear homogeneously branched ethylene polymers as well as ethylene-styrene interpolymers. The amount of such other polymers differs depending upon the elasticity desired and compatibility with the specific ethylene α-olefin interpolymer employed.

The heavy weight fabric provided herein often further comprises another material which often comprises fibers including any known natural and synthetic fibers, particularly inelastic fibers. Typical of these other fibers are cellulose, cotton, flax, ramie, rayon, nylon, viscose, hemp, wool, silk, linen, bamboo, tencel, mohair, polyester, polyamide, polypropylene, polyolefin, other cellulosic, protein, or synthetics, as well as, mixtures thereof. Usually the other fiber comprises from about 1 to about 99% of the heavy weight fabric provided herein. In one embodiment, the other material or fiber comprises less than about 99%, 98%, 97%, 96%, 95%, 94%, 93%, 92%, 90%, 88%, 85% of the fabric. In another embodiment, the other material or fiber comprises about 95%, 92% or 90% of the fabric.

If desired an additional stretch material may be employed in addition to the ethylene/α-olefin interpolymer. For example, the ethylene/α-olefin interpolymer fiber may be employed in either the warp or weft direction while the second stretch material is employed in the remaining direction. Suitable additional stretch materials may include elastic fibers comprised of a polymer selected from the group consisting of polybutylene terephthalate, spandex, poly(ethylene terephthalate), poly(trimethylene terephthalate), or mixtures thereof. Such mixtures include bicomponent fibers of poly(ethylene terephthalate)/poly(trimethylene terephthalate) such as, for example, T-400™ fibers. While the elasticity and properties vary depending upon the materials and construction of the fabric, it may be desirable to employ ethylene/α-olefin interpolymer fibers in the warp direction and the additional stretch material in the weft direction.

In certain embodiments, the ethylene/α-olefin interpolymer is in the form of a fiber having a gel content of from about 10% to about 75% (by weight). In certain embodiments, the ethylene/α-olefin interpolymer is in the form of a fiber having a gel content of from about 10%, 20%, 30%, 40%, 50%, 60% or about 75% (by weight). In certain embodiments, the ethylene/α-olefin interpolymer is in the form of a fiber having a gel content of at least about 10% (by weight). These fibers, whether neat or used with other material in a yarn, may be used alone or together with other yarns to make the heavy weight fabric, provided herein. The fabric provided herein can be made according to known fabrication methods such as weaving (where the elastic fiber can be in the warp direction, the weft direction or both) or knitting.

The fibers may be made into any desirable size and cross-sectional shape depending upon the desired application. For many applications approximately round cross-section is desirable due to its reduced friction. However, other shapes such as a trilobal shape, or a flat (i.e., “ribbon” like) shape can also be employed. Denier is a textile term which is defined as the grams of the fiber per 9000 meters of that fiber's length. Preferred sizes include a denier from at least about 1, preferably at least about 20, preferably at least about 50, to at most about 180, preferably at most about 150, preferably at most about 100 denier, preferably at most about 80 denier.

The fiber is usually elastic and usually cross-linked. The fiber comprises the reaction product of ethylene/α-olefin interpolymer and any suitable cross-linking agent, i.e., a cross-linked ethylene/α-olefin interpolymer. As used herein, “cross-linking agent” is any means which cross-links one or more, preferably a majority, of the fibers. Thus, cross-linking agents may be chemical compounds but are not necessarily so. Cross-linking agents as used herein also include electron-beam irradiation, beta irradiation, gamma irradiation, corona irradiation, silanes, peroxides, allyl compounds and UV radiation with or without crosslinking catalyst. U.S. Pat. Nos. 6,803,014 and 6,667,351 disclose electron-beam irradiation methods that can be used in embodiments of the invention. In some embodiments, the percent of cross-linked polymer is at least 10 percent, preferably at least about 20, more preferably at least about 25 weight percent to about at most 75, preferably at most about 50 percent, as measured by the weight percent of gels formed.

Depending upon the application the fiber may take any suitable form including a staple fiber or binder fiber. Typical examples may include a continuous filament, a homofil fibers, or a bicomponent fiber. In the case of a bicomponent fiber it may have a sheath-core structure; a sea-island structure; a side-by-side structure; a matrix-fibril structure; or a segmented pie structure. Advantageously, conventional fiber forming processes may be employed to make the aforementioned fibers. Such processes include those described in, for example,. U.S. Pat. Nos. 4,340,563; 4,663,220; 4,668,556; 4,322,027; and 4,413,440).

The fibers useful in the present invention facilitate processing in a number of respects. First, the inventive fibers unwind better from a spool than conventional fibers. Ordinary fibers when in round cross section often fail to provide satisfactory unwinding performance due to their base polymer excessive stress relaxation. This stress relaxation is proportional to the age of the spool and causes filaments located at the very surface of the spool to lose grip on the surface, becoming loose filament strands. Later, when such a spool containing conventional fibers is placed over the rolls of positive feeders, i.e. Memminger-IRO, and starts to rotate to industrial speeds, i.e. 100 to 300 rotations/minute, the loose fibers are thrown to the sides of the spool surface and ultimately fall off the edge of the spool. This failure is known as derails which denotes the tendency of conventional fibers to slip off the shoulder or edge of the package which disrupts the unwinding process and ultimately causes machine stops. The inventive fibers exhibit derailing to a much less significant degree which allows greater throughput.

A preferred fabric of the present invention is a denim-like fabric, as many current processes for treating denim, e.g., stone washing or bleaching, are too harsh for current elastic fabrics.

Preparation of Exemplary Heavy Weight Fabrics

The elastic fibers comprising ethylene α-olefin interpolymer for use in the fabrics provided herein can be formed by many processes known in the art. In one embodiment, an ethylene/α-olefin interpolymer fiber is made and then crosslinked to about 10% to 75% gel.

A core spun yarn is then prepared comprising ethylene/α-olefin interpolymer as the core and other staple or filament fibers, which may include cellulose, aramid, para-aramids, polyesters, wool, silk, etc. and blends thereof as the covering material. Typically, but not necessarily, each end of yarn comprises one or more elastic fibers that may include the ethylene/α-olefin interpolymer. The size range for the core spun yarn is typically 2 to 50 Ne in size. In one embodiment, the size range for the core spun yarn is 2 to 45, preferably 5 to 40, preferably 6 to 40, preferably 7 to 40, preferably 10 to 40, preferably 20 to 40, preferably 2 to 30, and more preferably 5 to 30 Ne. In one embodiment, the core spun yarn is used in the weft direction. In one embodiment, a core spun yarn comprising ethylene/α-olefin interpolymer in the count range of 6 to 40 Ne could also be used for the warp yarn to make a bi-stretch fabric.

The core yarn comprising ethylene/α-olefin interpolymer can be made by any means know in the art. For example, it could be covered with staple fibers by several methods including but not limited to ring, siro, air-jet, dref and rotor spinning with core attachments. The yarn comprising ethylene/α-olefin interpolymer could also be covered with filament yarns by single, double covering or air-jet covering. In one aspect, two or more core yarns are combined through a doubling or plying process. When two or more yarns that are combined, one comprises ethylene/α-olefin interpolymer core and other may comprise ethylene/α-olefin interpolymer and polyolefin blend having an overall melt index (I₂) less than or equal to about 2.5 g/10 min with an overall density. The core yarns may further comprise other polymers discussed herein. In one embodiment, the fiber is made by core spinning or siro spinning. In one aspect, the yarn count range for the weft yarns is from about 7 to about 15 Ne or from about 5 to about 40 Ne.

In one embodiment, the fabric construction for the fabric provided herein is a 2 to 1, 3 to 1 twill, or a plain weave. In another aspect, weave patterns like basket, dobby, jacquard, oxford, satin, canvas could also be used. Fabrics will typically be woven with every weft yarn containing a elastomeric core, but they could also be woven with every other yarn containing an elastomeric core and the other one with no elastomeric core. In certain embodiments, the fabrics are made with every warp yarn being identical in size, but it is also possible for the warp to contain yarns of different yarn sizes.

In one embodiment, the number of picks per inch is 20 to 70, preferably 30 to 60 or more preferably 40 to 50. In one preferred embodiment, the number of picks per inch is 40 to 50.

The fabric finishing steps often may comprise additional steps. Examples of typical finishing steps include one or more of the following steps: singeing, scouring, drying, softening, sanforizing, mercerizing, garment washing (stone washing, bleaching, decolorization, neutralization or rinsing, enzyme bleach, marble white finishing, soil release, no-iron treatments wrinkle resistant finishes, flame retardant finishes, etc). Preferably, fabric finishing includes singing, washing, drying and sanforizing. The critical temperatures needed to develop fabric shrinkage (and therefore stretch) are often accomplished during the washing steps and sometime are in the range of 40 to 140° C. or 60 to 125° C. In another embodiment, preferred finishing steps include singing, washing, softening, drying and sanforizing, compacting, application of stain release, wrinkle resistant, or flame retardant finishes. In certain embodiments, garment washing may also be employed after the fabric is sewn into a garment.

In one aspect, the fabric provided herein is denim. Denim is traditionally a textile often comprised of cotton in which the weft often passes under two (twi-“double”) or more warp fibers producing a somewhat diagonal ribbing on the reverse of the fabric. Many current processes for treating denim are too harsh for current elastic fabrics. Thus, denim made from elastic fabric provided herein will be able to survive the current treatments. In one embodiment, the fabric provided herein can then be used to make garments and/or upholstery. Examples of garments which can be made from the fabric comprise uniforms, particularly rental uniforms which are subject to industrial laundering.

Testing Methods

In the examples that follow, the following analytical techniques are employed:

GPC Method for Samples 1-4 and A-C

An automated liquid-handling robot equipped with a heated needle set to 160° C. is used to add enough 1,2,4-trichlorobenzene stabilized with 300 ppm Ionol to each dried polymer sample to give a final concentration of 30 mg/mL. A small glass stir rod is placed into each tube and the samples are heated to 160° C. for 2 hours on a heated, orbital-shaker rotating at 250 rpm. The concentrated polymer solution is then diluted to 1 mg/ml using the automated liquid-handling robot and the heated needle set to 160° C.

A Symyx Rapid GPC system is used to determine the molecular weight data for each sample. A Gilson 350 pump set at 2.0 ml/min flow rate is used to pump helium-purged 1,2-dichlorobenzene stabilized with 300 ppm Ionol as the mobile phase through three Plgel 10 micrometer (μm) Mixed B 300 mm×7.5 mm columns placed in series and heated to 160° C. A Polymer Labs ELS 1000 Detector is used with the Evaporator set to 250° C. the Nebulizer set to 165° C., and the nitrogen flow rate set to 1.8 SLM at a pressure of 60-80 psi (400−600 kPa) N₂. The polymer samples are heated to 160° C. and each sample injected into a 250 μl loop using the liquid-handling robot and a heated needle. Serial analysis of the polymer samples using two switched loops and overlapping injections are used. The sample data is collected and analyzed using Symyx Epoch™ software. Peaks are manually integrated and the molecular weight information reported uncorrected against a polystyrene standard calibration curve.

Standard CRYSTAF Method

Branching distributions are determined by crystallization analysis fractionation (CRYSTAF) using a CRYSTAF 200 unit commercially available from PolymerChar, Valencia, Spain. The samples are dissolved in 1,2,4 trichlorobenzene at 160° C. (0.66 mg/mL) for 1 hr and stabilized at 95° C. for 45 minutes. The sampling temperatures range from 95 to 30° C. at a cooling rate of 0.2° C./min. An infrared detector is used to measure the polymer solution concentrations. The cumulative soluble concentration is measured as the polymer crystallizes while the temperature is decreased. The analytical derivative of the cumulative profile reflects the short chain branching distribution of the polymer.

The CRYSTAF peak temperature and area are identified by the peak analysis module included in the CRYSTAL Software (Version 2001.b, PolymerChar, Valencia, Spain). The CRYSTAL peak finding routine identifies a peak temperature as a maximum in the dW/dT curve and the area between the largest positive inflections on either side of the identified peak in the derivative curve. To calculate the CRYSTAF curve, the preferred processing parameters are with a temperature limit of 70° C. and with smoothing parameters above the temperature limit of 0.1, and below the temperature limit of 0.3.

DSC Standard Method (Excluding Samples 1-4 and A-C)

Differential Scanning Calorimetry results are determined using a TAI model Q1000 DSC equipped with an RCS cooling accessory and an autosampler. A nitrogen purge gas flow of 50 ml/min is used. The sample is pressed into a thin film and melted in the press at about 175° C. and then air-cooled to room temperature (25° C.). 3-10 mg of material is then cut into a 6 mm diameter disk, accurately weighed, placed in a light aluminum pan (ca 50 mg), and then crimped shut. The thermal behavior of the sample is investigated with the following temperature profile. The sample is rapidly heated to 180° C. and held isothermal for 3 minutes in order to remove any previous thermal history. The sample is then cooled to −40° C. at 10° C./min cooling rate and held at −40° C. for 3 minutes. The sample is then heated to 150° C. at 10° C./min. heating rate. The cooling and second heating curves are recorded.

The DSC melting peak is measured as the maximum in heat flow rate (W/g) with respect to the linear baseline drawn between −30° C. and end of melting. The heat of fusion is measured as the area under the melting curve between −30° C. and the end of melting using a linear baseline.

GPC Method (Excluding Samples 1-4 and A-C)

The gel permeation chromatographic system consists of either a Polymer Laboratories Model PL-210 or a Polymer Laboratories Model PL-220 instrument. The column and carousel compartments are operated at 140° C. Three Polymer Laboratories 10-micron Mixed-B columns are used. The solvent is 1,2,4 trichlorobenzene. The samples are prepared at a concentration of 0.1 grams of polymer in 50 milliliters of solvent containing 200 ppm of butylated hydroxytoluene (BHT). Samples are prepared by agitating lightly for 2 hours at 160° C. The injection volume used is 100 microliters and the flow rate is 1.0 ml/minute.

Calibration of the GPC column set is performed with 21 narrow molecular weight distribution polystyrene standards with molecular weights ranging from 580 to 8,400,000, arranged in 6 “cocktail” mixtures with at least a decade of separation between individual molecular weights. The standards are purchased from Polymer Laboratories (Shropshire, UK). The polystyrene standards are prepared at 0.025 grams in 50 milliliters of solvent for molecular weights equal to or greater than 1,000,000, and 0.05 grams in 50 milliliters of solvent for molecular weights less than 1,000.000. The polystyrene standards are dissolved at 80° C. with gentle agitation for 30 minutes. The narrow standards mixtures are run first and in order of decreasing highest molecular weight component to minimize degradation. The polystyrene standard peak molecular weights are converted to polyethylene molecular weights using the following equation (as described in Williams and Ward, J. Polym. Sci., Polym. Let., 6,621 (1968)) M_(polyethylene)=0.431 (M_(polystyrene)).

Polyethylene equivalent molecular weight calculations are performed using Viscotek TriSEC software Version 3.0.

Compression Set

Compression set is measured according to ASTM D 395. The sample is prepared by stacking 25.4 mm diameter round discs of 3.2 mm, 2.0 mm, and 0.25 mm thickness until a total thickness of 12.7 mm is reached. The discs are cut from 12.7 cm×12.7 cm compression molded plaques molded with a hot press under the following conditions: zero pressure for 3 min at 190° C., followed by 86 MPa for 2 min at 190° C., followed by cooling inside the press with cold running water at 86 MPa.

Density

Samples for density measurement are prepared according to ASTM D 1928. Measurements are made within one hour of sample pressing using ASTM D792, Method B.

Flexural/Secant Modulus/Storage Modulus

Samples are compression molded using ASTM D 1928. Flexural and 2 percent secant moduli are measured according to ASTM D-790. Storage modulus is measured according to ASTM D 5026-01 or equivalent technique.

Optical Properties

Films of 0.4 mm thickness are compression molded using a hot press (Carver Model #4095-4PR1001R). The pellets are placed between polytetrafluoroethylene sheets, heated at 190° C. at 55 psi (380 kPa) for 3 min followed by 1.3 MPa for 3 min, and then 2.6 MPa for 3 min. The film is then cooled in the press with running cold water at 1.3 MPa for 1 min. The compression molded films are used for optical measurements, tensile behavior, recovery, and stress relaxation.

Clarity is measured using BYK Gardner Haze-gard as specified in ASTM D 1746.

45° gloss is measured using BYK Gardner Glossmeter Microgloss 45° as specified in ASTM D-2457

Internal haze is measured using BYK Gardner Haze-gard based on ASTM D 1003 Procedure A. Mineral oil is applied to the film surface to remove surface scratches.

Mechanical Properties—Tensile, Hysteresis, and Tear

Stress-strain behavior in uniaxial tension is measured using ASTM D 1708 microtensile specimens. Samples are stretched with an Instron at 500% min⁻ at 21° C. Tensile strength and elongation at break are reported from an average of 5 specimens.

100% and 300% Hysteresis is determined from cyclic loading to 100% and 300% strains using ASTM D 1708 microtensile specimens with an Instron™ instrument. The sample is loaded and unloaded at 267% min-1 for 3 cycles at 21° C. Cyclic experiments at 300% and 80° C. are conducted using an environmental chamber. In the 80° C. experiment, the sample is allowed to equilibrate for 45 minutes at the test temperature before testing. In the 21° C., 300% strain cyclic experiment, the retractive stress at 150% strain from the first unloading cycle is recorded. Percent recovery for all experiments are calculated from the first unloading cycle using the strain at which the load returned to the base line. The percent recovery is defined as:

${\% \mspace{14mu} {Recovery}} = {\frac{ɛ_{f} - ɛ_{s}}{ɛ_{f}} \times 100}$

where ε_(f) is the strain taken for cyclic loading and ε_(s) is the strain where the load returns to the baseline during the 1^(st) unloading cycle.

Stress relaxation is measured at 50 percent strain and 37° C. for 12 hours using an Instron™ instrument equipped with an environmental chamber. The gauge geometry was 76 mm×25 mm×0.4 mm. After equilibrating at 37° C. for 45 min in the environmental chamber, the sample was stretched to 50% strain at 333% min⁻. Stress was recorded as a function of time for 12 hours. The percent stress relaxation after 12 hours was calculated using the formula:

${\% \mspace{14mu} {Stress}\mspace{14mu} {Relaxation}} = {\frac{L_{0} - L_{12}}{L_{0}} \times 100}$

where L₀ is the load at 50% strain at 0 time and L₁₂ is the load at 50 percent strain after 12 hours.

Tensile notched tear experiments are carried out on samples having a density of 0.88 g/cc or less using an Instron™ instrument. The geometry consists of a gauge section of 76 mm×13 mm×0.4 mm with a 2 mm notch cut into the sample at half the specimen length. The sample is stretched at 508 mm min-1 at 21° C. until it breaks. The tear energy is calculated as the area under the stress-elongation curve up to strain at maximum load. An average of at least 3 specimens are reported.

TMA

Thermal Mechanical Analysis (Penetration Temperature) is conducted on 30 mm diameter×3.3 mm thick, compression molded discs, formed at 180° C. and 10 MPa molding pressure for 5 minutes and then air quenched. The instrument used is a TMA 7, brand available from Perkin-Elmer. In the test, a probe with 1.5 mm radius tip (P/N N519-0416) is applied to the surface of the sample disc with 1N force. The temperature is raised at 5° C./min from 25° C. The probe penetration distance is measured as a function of temperature. The experiment ends when the probe has penetrated 1 mm into the sample.

DMA

Dynamic Mechanical Analysis (DMA) is measured on compression molded disks formed in a hot press at 180° C. at 10 MPa pressure for 5 minutes and then water cooled in the press at 90° C., min. Testing is conducted using an ARES controlled strain rheometer (TA instruments) equipped with dual cantilever fixtures for torsion testing.

A 1.5 mm plaque is pressed and cut in a bar of dimensions 32×12 mm. The sample is clamped at both ends between fixtures separated by 10 mm (grip separation ΔL) and subjected to successive temperature steps from −100° C. to 200° C. (5° C. per step). At each temperature the torsion modulus G is measured at an angular frequency of 10 rad/s, the strain amplitude being maintained between 0.1 percent and 4 percent to ensure that the torque is sufficient and that the measurement remains in the linear regime.

An initial static force of 10 g is maintained (auto-tension mode) to prevent slack in the sample when thermal expansion occurs. As a consequence, the grip separation ΔL increases with the temperature, particularly above the melting or softening point of the polymer sample. The test stops at the maximum temperature or when the gap between the fixtures reaches 65 mm.

Melt Index

Melt index, or I₂, is measured in accordance with ASTM D 1238, Condition 190° C./2.16 kg. Melt index, or I₁₀ is also measured in accordance with ASTM D 1238, Condition 190° C./10 kg.

ATREF

Analytical temperature rising elution fractionation (ATREF) analysis is conducted according to the method described in U.S. Pat. No. 4,798,081 and Wilde, L,; Ryle, T. R.; Knobeloch, D. C.; Peat, I. R.; Determination of Branching Distributions in Polyethylene and Ethylene Copolymers, J. Polym. Sci., 20, 441-455 (1982), which are incorporated by reference herein in their entirety. The composition to be analyzed is dissolved in trichlorobenzene and allowed to crystallize in a column containing an inert support (stainless steel shot) by slowly reducing the temperature to 20° C. at a cooling rate of 0.1° C./min. The column is equipped with an infrared detector. An ATREF chromatogram curve is then generated by eluting the crystallized polymer sample from the column by slowly increasing the temperature of the eluting solvent (trichlorobenzene) from 20 to 120° C. at a rate of 1.5° C./min.

¹³C NMR Analysis

The samples are prepared by adding approximately 3 g of a 50/50 mixture of tetrachloroethane-d²/orthodichlorobenzene to 0.4 g sample in a 10 mm NMR tube. The samples are dissolved and homogenized by heating the tube and its contents to 150° C. The data are collected using a JEOL Eclipse™ 400MHz spectrometer or a Varian Unity Plus™ 400 MHz spectrometer, corresponding to a ¹³C resonance frequency of 100.5 MHz. The data are acquired using 4000 transients per data file with a 6 second pulse repetition delay. To achieve minimum signal-to-noise for quantitative analysis, multiple data files are added together. The spectral width is 25,000 Hz with a minimum file size of 32K data points. The samples are analyzed at 130° C. in a 10 mm broad band probe. The comonomer incorporation is determined using Randall's triad method (Randall, J. C.; JMS-Rev. Macromol. Chem. Phys., C29, 201-317 (1989), which is incorporated by reference herein in its entirety.

Polymer Fractionation by TREF

Large-scale TREF fractionation is carried by dissolving 15-20 g of polymer in 2 liters of 1,2,4-trichlorobenzene (TCB) by stirring for 4 hours at 160° C. The polymer solution is forced by 15 psig (100 kPa) nitrogen onto a 3 inch by 4 foot (7.6 cm×12 cm) steel column packed with a 60:40 (v:v) mix of 30-40 mesh (600-425 μm) spherical, technical quality glass beads (available from Potters Industries, HC 30 Box 20, Brownwood, Tex., 76801) and stainless steel, 0.028″ (0.7 mm) diameter cut wire shot (available from Pellets, Inc. 63 Industrial Drive, North Tonawanda, N.Y., 14120). The column is immersed in a thermally controlled oil jacket, set initially to 160° C. The column is first cooled ballistically to 125° C., then slow cooled to 20° C. at 0.04° C. per minute and held for one hour. Fresh TCB is introduced at about 65 ml/min while the temperature is increased at 0.167° C. per minute.

Approximately 2000 ml portions of eluant from the preparative TREF column are collected in a 16 station, heated fraction collector. The polymer is concentrated in each fraction using a rotary evaporator until about 50 to 100 ml of the polymer solution remains. The concentrated solutions are allowed to stand overnight before adding excess methanol, filtering, and rinsing (approx. 300-500 ml of methanol including the final rinse). The filtration step is performed on a 3 position vacuum assisted filtering station using 5.0 μm polytetrafluoroethylene coated filter paper (available from Osmonics Inc. Cat# Z50WP04750). The filtrated fractions are dried overnight in a vacuum oven at 60° C. and weighed on an analytical balance before further testing.

Melt Strength

Melt Strength (MS) is measured by using a capillary rheometer fitted with a 2.1 mm diameter, 20:1 die with an entrance angle of approximately 45 degrees. After equilibrating the samples at 190° C. for 10 minutes, the piston is run at a speed of 1 inch/minute (2.54 cm/minute). The standard test temperature is 190° C. The sample is drawn uniaxially to a set of accelerating nips located 100 mm below the die with an acceleration of 2.4 mm sec². The required tensile force is recorded as a function of the take-up speed of the nip rolls. The maximum tensile force attained during the test is defined as the melt strength. In the case of polymer melt exhibiting draw resonance, the tensile force before the onset of draw resonance was taken as melt strength. The melt strength is recorded in centiNewtons (“cN”).

Catalysts

The term “overnight”, if used, refers to a time of approximately 16-18 hours, the term “room temperature”, refers to a temperature of 20-25° C. and the term “mixed alkanes” refers to a commercially obtained mixture of C₆₋₉ aliphatic hydrocarbons available under the trade designation Isopar E® from ExxonMobil Chemical Company. In the event the name of a compound herein does not conform to the structural representation thereof, the structural representation shall control. The synthesis of all metal complexes and the preparation of all screening experiments were carried out in a dry nitrogen atmosphere using dry box techniques. All solvents used were HPLC grade and were dried before their use.

MMAO refers to modified methylalumoxane, a triisobutylaluminum modified methylalumoxane available commercially from Akzo-Noble Corporation.

The preparation of catalyst (B1) is conducted as follows.

a) Preparation of (1-methylethyl)(2-hydroxy-3,5-di(t-butyl)phenyl)methylimine

3,5-Di-t-butylsalicylaidehyde (3.00 g) is added to 10 mL of isopropylamine. The solution rapidly turns bright yellow. After stirring at ambient temperature for 3 hours, volatiles are removed under vacuum to yield a bright yellow, crystalline solid (97 percent yield).

b) Preparation of 1,2-bis-(3,5-di-t-butylphenylene)(1-(N-(1-methylethyl)immino)methyl)(2-oxoyl)zirconium dibenzyl

A solution of (1-methylethyl)(2-hydroxy-3,5-di(t-butyl)phenyl)imine (605 mg, 2.2 mmol) in 5 mL toluene is slowly added to a solution of Zr(CH₂Ph)₄ (500 mg, 1.1 mmol) in 50 mL toluene. The resulting dark yellow solution is stirred for 30 min. Solvent is removed under reduced pressure to yield the desired product as a reddish-brown solid.

The preparation of catalyst (B2) is conducted as follows.

a) Preparation of (1-(2-methylcyclohexyl)ethyl)(2-oxoyl-3,5-di(t-butyl)phenyl)imine

2-Methylcyclohexylamine (8.44 mL, 64.0 mmol) is dissolved in methanol (90 ml), and di-t-butylsalicaldehyde (10.00 g, 42.67 mmol) is added. The reaction mixture is stirred for three hours and then cooled to −25° C. for 12 hrs. The resulting yellow solid precipitate is collected by filtration and washed with cold methanol (2×15 mL) and then dried under reduced pressure. The yield is 11.17 g of a yellow solid. ¹H NMR is consistent with the desired product as a mixture of isomers.

b) Preparation of bis-(1-(2-methylcyclohexyl)ethyl)(2-oxoyl-3,5-di(t-butyl)phenyl)immino)zirconium dibenzyl

A solution of (1-(2-methylcyclohexyl)ethyl)(2-oxoyl-3,5-di(t-butyl)phenyl)imine (7.63 g, 23.2 mmol) in 200 mL toluene is slowly added to a solution of Zr(CH₂Ph)₄ (5.28 g, 11.6 mmol) in 600 mL toluene. The resulting dark yellow solution is stirred for 1 hour at 25° C. The solution is diluted further with 680 mL toluene to give a solution having a concentration of 0.00783 M.

Cocatalyst 1 A mixture of methyldi(C₁₄₋₁₈ alkyl)ammonium salts of tetrakis(pentafluorophenyl)borate (here-in-after armeenium borate), prepared by reaction of a long chain trialkylamine (Armeen™ M2HT, available from Akzo-Nobel, Inc.). HCl and Li[B(C₆F₅)₄], substantially as disclosed in USP 5,919,9883, Ex. 2.

Cocatalyst 2 Mixed C₁₄₋₁₈ alkyldimethylammonium salt of bis(tris(pentafluorophenyl)-alumane)-2-undecyl imidazolide, prepared according to U.S. Pat. No. 6,395,671, Ex. 16.

Shuttling Agents The shuttling agents employed include diethylzinc (DEZ, SA1), di(1-butyl)zinc (SA2), di(n-hexyl)zinc (SA3), triethylaluminum (TEA, SA4), trioctylaluminum (SA5), triethylgallium (SA6), i-butylaluminum bis(dimethyl(t-butyl)siloxane) (SA7), i-butylaluminum bis(di(trimethylsilyl)amide) (SA8), n-octylaluminum di(pyridine-2-methoxide) (SA9), bis(n-octadecyl)i-butylaluminum (SA10), i-butylaluminum bis(di(n-pentyl)amide) (SA 11), n-octylaluminum bis(2,6-di-t-butylphenoxide) (SA12), n-octylaluminum di(ethyl(1-naphthyl)amide) (SA13), ethylaluminum bis(t-butyldimethylsiloxide) (SA14), ethylaluminum di(bis(trimethylsilyl)amide) (SA15), ethylaluminum bis(2,3,6,7-dibenzo-1-azacycloheptaneamide) (SA 16), n-octylaluminum bis(2,3,6,7-dibenzo-1-azacycloheptaneamide) (SA17), n-octyl aluminum bis(dimethyl(t-butyl)siloxide(SA18), ethylzinc (2,6-diphenylphenoxide) (SA19), and ethylzinc (t-butoxide) (SA20).

EXAMPLES 1-4 Comparative A-C General High Throughput Parallel Polymerization Conditions

Polymerizations are conducted using a high throughput, parallel polymerization reactor (PPR) available from Symyx Technologies, Inc. and operated substantially according to U.S. Pat. Nos. 6,248,540, 6,030,917, 6,362,309, 6,306,658, and 6,316,663. Ethylene copolymerizations are conducted at 130° C. and 200 psi (1.4 MPa) with ethylene on demand using 1.2 equivalents of cocatalyst 1 based on total catalyst used (1.1 equivalents when MMAO is present). A series of polymerizations are conducted in a parallel pressure reactor (PPR) contained of 48 individual reactor cells in a 6×8 array that are fitted with a pre-weighed glass tube. The working volume in each reactor cell is 6000 μL. Each cell is temperature and pressure controlled with stirring provided by individual stirring paddles. The monomer gas and quench gas are plumbed directly into the PPR unit and controlled by automatic valves. Liquid reagents are robotically added to each reactor cell by syringes and the reservoir solvent is mixed alkanes. The order of addition is mixed alkanes solvent (4 ml), ethylene, 1-octene comonomer (1 ml), cocatalyst 1 or cocatalyst 1/MMAO mixture, shuttling agent, and catalyst or catalyst mixture.

When a mixture of cocatalyst 1 and MMAO or a mixture of two catalysts is used, the reagents are premixed in a small vial immediately prior to addition to the reactor. When a reagent is omitted in an experiment, the above order of addition is otherwise maintained. Polymerizations are conducted for approximately 1-2 minutes, until predetermined ethylene consumptions are reached. After quenching with CO, the reactors are cooled and the glass tubes are unloaded. The tubes are transferred to a centrifuge/vacuum drying unit, and dried for 12 hours at 60° C. The tubes containing dried polymer are weighed and the difference between this weight and the tare weight gives the net yield of polymer. Results are contained in Table 1. In Table 1 and elsewhere in the application, comparative compounds are indicated by an asterisk (*).

Examples 1-4 demonstrate the synthesis of linear block copolymers by the present invention as evidenced by the formation of a very narrow MWD, essentially monomodal copolymer when DEZ is present and a bimodal, broad molecular weight distribution product (a mixture of separately produced polymers) in the absence of DEZ. Due to the fact that Catalyst (A1) is known to incorporate more octene than Catalyst (B1), the different blocks or segments of the resulting copolymers of the invention are distinguishable based on branching or density.

TABLE 1 Cat. (A1) Cat (B1) Cocat MMAO shuttling Ex. (μmol) (μmol) (μmol) (μmol) agent (μmol) Yield (g) Mn Mw/Mn hexyls¹ A* 0.06 — 0.066 0.3 — 0.1363 300502 3.32 — B* — 0.1 0.110 0.5 — 0.1581 36957 1.22 2.5 C* 0.06 0.1 0.176 0.8 — 0.2038 45526 5.30² 5.5 1 0.06 0.1 0.192 — DEZ (8.0)  0.1974 28715 1.19 4.8 2 0.06 0.1 0.192 — DEZ (80.0) 0.1468 2161 1.12 14.4  3 0.06 0.1 0.192 — TEA (8.0)  0.208 22675 1.71 4.6 4 0.06 0.1 0.192 — TEA (80.0) 0.1879 3338 1.54 9.4 ¹C₆ or higher chain content per 1000 carbons ²Bimodal molecular weight distribution

It may be seen the polymers produced according to the invention have a relatively narrow polydispersity (Mw/Mn) and larger block-copolymer content (trimer, tetramer, or larger) than polymers prepared in the absence of the shuttling agent.

Further characterizing data for the polymers of Table 1 are determined by reference to the figures. More specifically DSC and ATREF results show the following:

The DSC curve for the polymer of example 1 shows a 115.7° C. melting point (Tm) with a heat of fusion of 158.1 J/g. The corresponding CRYSTAF curve shows the tallest peak at 34.5° C. with a peak area of 52.9 percent. The difference between the DSC Tm and the Tcrystaf is 81.2° C.

The DSC curve for the polymer of example 2 shows a peak with a 109.7° C. melting point (Tm) with a heat of fusion of 214.0 J/g. The corresponding CRYSTAF curve shows the tallest peak at 46.2° C. with a peak area of 57.0 percent. The difference between the DSC Tm and the Tcrystaf is 63.5° C.

The DSC curve for the polymer of example 3 shows a peak with a 120.7° C. melting point (Tm) with a heat of fusion of 160.1 J/g. The corresponding CRYSTAF curve shows the tallest peak at 66.1° C. with a peak area of 71.8 percent. The difference between the DSC Tm and the Tcrystaf is 54.6° C.

The DSC curve for the polymer of example 4 shows a peak with a 104.5° C. melting point (Tm) with a heat of fusion of 170.7 J/g. The corresponding CRYSTAF curve shows the tallest peak at 30 PC with a peak area of 18.2 percent. The difference between the DSC Tm and the Tcrystaf is 74.5° C.

The DSC curve for comparative A shows a 90.0° C. melting point (Tm) with a heat of fusion of 86.7 J/g. The corresponding CRYSTAF curve shows the tallest peak at 48.50° C. with a peak area of 29.4 percent. Both of these values are consistent with a resin that is low in density. The difference between the DSC Tm and the Tcrystaf is 41.8° C.

The DSC curve for comparative B shows a 129.8° C. melting point (Tm) with a heat of fusion of 237.0 J/g. The corresponding CRYSTAF curve shows the tallest peak at 82.4° C. with a peak area of 83.7 percent. Both of these values are consistent with a resin that is high in density. The difference between the DSC Tm and the Tcrystaf is 47.4° C.

The DSC curve for comparative C shows a 125.3° C. melting point (Tm) with a heat of fusion of 143.0 J/g. The corresponding CRYSTAF curve shows the tallest peak at 81.8° C. with a peak area of 34.7 percent as well as a lower crystalline peak at 52.4° C. The separation between the two peaks is consistent with the presence of a high crystalline and a low crystalline polymer. The difference between the DSC Tm and the Tcrystaf is 43.5° C.

EXAMPLES 5-19 Comparatives D-F, Continuous Solution Polymerization, Catalyst A1/B2+DEZ

Continuous solution polymerizations are carried out in a computer controlled autoclave reactor equipped with an internal stirrer. Purified mixed alkanes solvent (Isopar™ E available from ExxonMobil Chemical Company), ethylene at 2.70 lbs/hour (1.22 kg/hour), 1-octene, and hydrogen (where used) are supplied to a 3.8 L reactor equipped with a jacket for temperature control and an internal thermocouple. The solvent feed to the reactor is measured by a mass-flow controller. A variable speed diaphragm pump controls the solvent flow rate and pressure to the reactor. At the discharge of the pump, a side stream is taken to provide flush flows for the catalyst and cocatalyst 1 injection lines and the reactor agitator. These flows are measured by Micro-Motion mass flow meters and controlled by control valves or by the manual adjustment of needle valves. The remaining solvent is combined with 1-octene, ethylene, and hydrogen (where used) and fed to the reactor. A mass flow controller is used to deliver hydrogen to the reactor as needed. The temperature of the solvent/monomer solution is controlled by use of a heat exchanger before entering the reactor. This stream enters the bottom of the reactor. The catalyst component solutions are metered using pumps and mass flow meters and are combined with the catalyst flush solvent and introduced into the bottom of the reactor. The reactor is run liquid-full at 500 psig (3.45 MPa) with vigorous stirring. Product is removed through exit lines at the top of the reactor. All exit lines from the reactor are steam traced and insulated. Polymerization is stopped by the addition of a small amount of water into the exit line along with any stabilizers or other additives and passing the mixture through a static mixer. The product stream is then heated by passing through a heat exchanger before devolatilization. The polymer product is recovered by extrusion using a devolatilizing extruder and water cooled pelletizer. Process details and results are contained in Table 2. Selected polymer properties are provided in Table 3

TABLE 2 Process details for preparation of exemplary polymers Cat Cat A1 Cat B2 DEZ DEZ C₈H₁₆ Solv. H₂ T A1² Flow B2³ Flow Conc Flow Ex. kg/hr kg/hr sccm¹ ° C. ppm kg/hr ppm kg/hr % kg/hr D* 1.63 12.7 29.90 120 142.2  0.14 — — 0.19 0.32 E* ″ 9.5 5.00 ″ — — 109   0.10 0.19 0.32 F* ″ 11.3 251.6 ″ 71.7 0.06 30.8 0.06 — —  5 ″ ″ — ″ ″ 0.14 30.8 0.13 0.17 0.43  6 ″ ″ 4.92 ″ ″ 0.10 30.4 0.08 0.17 0.32  7 ″ ″ 21.70 ″ ″ 0.07 30.8 0.06 0.17 0.25  8 ″ ″ 36.90 ″ ″ 0.06 ″ ″ ″ 0.10  9 ″ ″ 78.43 ″ ″ ″ ″ ″ ″ 0.04 10 ″ ″ 0.00 123 71.1 0.12 30.3 0.14 0.34 0.19 11 ″ ″ ″ 120 71.1 0.16 ″ 0.17 0.80 0.15 12 ″ ″ ″ 121 71.1 0.15 ″ 0.07 ″ 0.09 13 ″ ″ ″ 122 71.1 0.12 ″ 0.06 ″ 0.05 14 ″ ″ ″ 120 71.1 0.05 ″ 0.29 ″ 0.10 15 2.45 ″ ″ ″ 71.1 0.14 ″ 0.17 ″ 0.14 16 ″ ″ ″ 122 71.1 0.10 ″ 0.13 ″ 0.07 17 ″ ″ ″ 121 71.1 0.10 ″ 0.14 ″ 0.08 18 0.69 ″ ″ 121 71.1 ″ ″ 0.22 ″ 0.11 19 0.32 ″ ″ 122 71.1 0.06 ″ ″ ″ 0.09 Cocat Cocat Poly Conc. Flow [C₂H₄]/ Rate⁵ Conv Solids Ex. ppm kg/hr [DEZ]⁴ kg/hr %⁶ % Eff.⁷ D* 820 0.17 536 1.81 88.8 l1.2 95.2 E* 1743 0.40 485 1.47 89.9 11.3 126.8 F* ″ 0.11 — 1.55 88.5 10.3 257.7  5 ″ 0.26 419 1.64 89.6 11.1 118.3  6 ″ 0.18 570 1.65 89.3 11.1 172.7  7 ″ 0.13 718 1.60 89.2 10.6 244.1  8 ″ 0.12 1778  1.62 90.0 10.8 261.1  9 ″ ″ 4596  1.63 90.2 10.8 267.9 10 1743 0.08 415 1.67 90.31 11.1 131.1 11 1743 0.10 249 1.68 89.56 11.1 100.6 12 1743 0.07 396 1.70 90.02 11.3 137.0 13 1743 0.05 653 1.69 89.64 11.2 161.9 14 1743 0.10 395 1.41 89.42 9.3 114.1 15 1743 0.09 282 1.80 89.33 11.3 121.3 16 1743 0.07 485 1.78 90.11 11.2 159.7 17 1743 ″ 506 1.75 89.08 11.0 155.6 18 1743 0.10 331 1.25 89.93 8.8 90.2 19 1743 0.08 367 1.16 90.74 8.4 106.0 *Comparative, not an example of the invention ¹standard cm³/min ²[N-(2,6-di(1-methylethyl)phenyl)amido)(2-isopropylphenyl)(α-naphthalen-2-diyl(6-pyridin-2-diyl)methane)] hafnium dimethyl ³bis-(1-(2-methylcyclohexy)ethyl) (2-oxoyl-3,5-di(t-butyl)phenyl)immino) zirconium dibenzyl ⁴molar ratio in reactor ⁵polymer production rate ⁶percent ethylene conversion in reactor ⁷efficiency, kg polymer/g M where g M = g Hf + g Zr

TABLE 3 Properties of exemplary polymers Heat of Density Mw Mn Fusion Ex. (g/cm³) I₂ I₁₀ I₁₀/I₂ (g/mol) (g/mol) Mw/Mn (J/g) D* 0.8627 1.5 10.0 6.5 110,000 55,800 2.0 32 E* 0.9378 7.0 39.0 5.6 65,000 33,300 2.0 183 F* 0.8895 0.9 12.5 13.4 137,300 9,980 13.8 90  5 0.8786 1.5 9.8 6.7 104,600 53,200 2.0 55  6 0.8785 1.1 7.5 6.5 109600 53300 2.1 55  7 0.8825 1.0 7.2 7.1 118,500 53,100 2.2 69  8 0.8828 0.9 6.8 7.7 129,000 40,100 3.2 68  9 0.8836 1.1 9.7 9.1 129600 28700 4.5 74 10 0.8784 1.2 7.5 6.5 113,100 58,200 1.9 54 11 0.8818 9.1 59.2 6.5 66,200 36,500 1.8 63 12 0.8700 2.1 13.2 6.4 101,500 55,100 1.8 40 13 0.8718 0.7 4.4 6.5 132,100 63,600 2.1 42 14 0.9116 2.6 15.6 6.0 81,900 43,600 1.9 123 15 0.8719 6.0 41.6 6.9 79,900 40,100 2.0 33 16 0.8758 0.5 3.4 7.1 148,500 74,900 2.0 43 17 0.8757 1.7 11.3 6.8 107,500 54,000 2.0 43 18 0.9192 4.1 24.9 6.1 72,000 37,900 1.9 136 19 0.9344 3.4 20.3 6.0 76,800 39,400 1.9 169 Tm- CRYSTAF T_(m) T_(c) T_(CRYSTAF) T_(CRYSTAF) Peak Area Ex. (° C.) (° C.) (° C.) (° C.) (percent) D* 37 45 30 7 99 E* 124 133 79 45 95 F* 125 111 78 47 20  5 120 101 48 72 60  6 115 94 44 71 63  7 121 103 49 72 29  8 124 106 80 43 13  9 125 109 81 44 16 10 116 92 41 75 52 11 114 93 40 74 25 12 113 80 30 83 91 13 114 80 30 81 8 14 121 106 73 48 92 15 114 91 32 82 10 16 117 96 48 69 65 17 116 96 43 73 57 18 120 106 70 50 94 19 125 112 80 45 88

The resulting polymers are tested by DSC and ATREF as with previous examples. Results are as follows:

The DSC curve for the polymer of example 5 shows a peak with a 119.6° C. melting point (Tm) with a heat of fusion of 60.0 J/g. The corresponding CRYSTAF curve shows the tallest peak at 47.6° C. with a peak area of 59.5 percent. The delta between the DSC Tm and the Tcrystaf is 72.0° C.

The DSC curve for the polymer of example 6 shows a peak with a 115.2° C. melting point (Tm) with a heat of fusion of 60.4 J/g. The corresponding CRYSTAF curve shows the tallest peak at 44.2° C. with a peak area of 62.7 percent. The delta between the DSC Tm and the Tcrystaf is 71.0° C.

The DSC curve for the polymer of example 7 shows a peak with a 121.3° C. melting point with a heat of fusion of 69.1 J/g. The corresponding CRYSTAF curve shows the tallest peak at 49.2° C. with a peak area of 29.4 percent. The delta between the DSC Tm and the Tcrystaf is 72.1° C.

The DSC curve for the polymer of example 8 shows a peak with a 123.5° C. melting point (Tm) with a heat of fusion of 67.9 J/g. The corresponding CRYSTAF curve shows the tallest peak at 80.1° C. with a peak area of 12.7 percent. The delta between the DSC Tm and the Tcrystaf is 43.4° C.

The DSC curve for the polymer of example 9 shows a peak with a 124.6° C. melting point (Tm) with a heat of fusion of 73.5 J/g. The corresponding CRYSTAF cure shows the tallest peak at 80.8° C. with a peak area of 16.0 percent. The delta between the DSC Tm and the Tcrystaf is 43.8° C.

The DSC curve for the polymer of example 10 shows a peak with a 115.6° C. melting point (Tm) with a heat of fusion of 60.7 J/g. The corresponding CRYSTAF curve shows the tallest peak at 40.9° C. with a peak area of 52.4 percent. The delta between the DSC Tm and the Tcrystaf is 74.7° C.

The DSC curve for the polymer of example 11 shows a peak with a 113.6° C. melting point (Tm) with a heat of fusion of 70.4 J/g. The corresponding CRYSTAF curve shows the tallest peak at 39.6° C. with a peak area of 25.2 percent. The delta between the DSC Tm and the Tcrystaf is 74.1° C.

The DSC curve for the polymer of example 12 shows a peak with a 113.2° C. melting point (Tm) with a heat of fusion of 48.9 J/g. The corresponding CRYSTAF curve shows no peak equal to or above 30° C. (Tcrystaf for purposes of further calculation is therefore set at 30° C.). The delta between the DSC Tm and the Tcrystaf is 83.2° C.

The DSC curve for the polymer of example 13 shows a peak with a 114.4° C. melting point (Tm) with a heat of fusion of 49.4 J/g. The corresponding CRYSTAF curve shows the tallest peak at 33.8° C. with a peak area of 7.7 percent. The delta between the DSC Tm and the Tcrystaf is 84.4° C.

The DSC for the polymer of example 14 shows a peak with a 120.8° C. melting point (Tm) with a heat of fusion of 127.9 J/g. The corresponding CRYSTAF curve shows the tallest peak at 72.9° C. with a peak area of 92.2 percent. The delta between the DSC Tm and the Tcrystaf is 47.9° C.

The DSC curve for the polymer of example 15 shows a peak with a 114.3° C. melting point (Tm) with a heat of fusion of 36.2 J/g. The corresponding CRYSTAF curve shows the tallest peak at 32.3° C. with a peak area of 9.8 percent. The delta between the DSC Tm and the Tcrystaf is 82.0° C.

The DSC curve for the polymer of example 16 shows a peak with a 116.6° C. melting point (Tm) with a heat of fusion of 44.9 J/g. The corresponding CRYSTAF curve shows the tallest peak at 48.0° C. with a peak area of 65.0 percent. The delta between the DSC Tm and the Tcrystaf is 68.6° C.

The DSC curve for the polymer of example 17 shows a peak with a 116.0° C. melting point (Tm) with a heat of fusion of 47.0 J/g. The corresponding CRYSTAF curve shows the tallest peak at 43.1° C. with a peak area of 56.8 percent. The delta between the DSC Tm and the Tcrystaf is 72.9° C.

The DSC curve for the polymer of example 18 shows a peak with a 120.5° C. melting point (Tm) with a heat of fusion of 141.8 J/g. The corresponding CRYSTAF curve shows the tallest peak at 70.0° C. with a peak area of 94.0 percent. The delta between the DSC Tm and the Tcrystaf is 50.5° C.

The DSC curve for the polymer of example 19 shows a peak with a 124.8° C. melting point (Tm) with a heat of fusion of 174.8 J/g. The corresponding CRYSTAF curve shows the tallest peak at 79.9° C. with a peak area of 87.9 percent. The delta between the DSC Tm and the Tcrystaf is 45.0° C.

The DSC curve for the polymer of comparative D shows a peak with a 37.3° C. melting point (Tm) with a heat of fusion of 31.6 μg. The corresponding CRYSTAF curve shows no peak equal to and above 30° C. Both of these values are consistent with a resin that is low in density. The delta between the DSC Tm and the Tcrystaf is 7.3° C.

The DSC curve for the polymer of comparative E shows a peak with a 124.0° C. melting point (Tm) with a heat of fusion of 179.3 J/g. The corresponding CRYSTAF curve shows the tallest peak at 79.3° C. with a peak area of 94.6 percent. Both of these values are consistent with a resin that is high in density. The delta between the DSC Tm and the Tcrystaf is 44.6° C.

The DSC curve for the polymer of comparative F shows a peak with a 124.8° C. melting point (Tm) with a heat of fusion of 90.4 J/g. The corresponding CRYSTAF curve shows the tallest peak at 77.6° C. with a peak area of 19.5 percent. The separation between the two peaks is consistent with the presence of both a high crystalline and a low crystalline polymer. The delta between the DSC Tm and the Tcrystaf is 47.2° C.

Physical Property Testing

Polymer samples are evaluated for physical properties such as high temperature resistance properties, as evidenced by TMA temperature testing, pellet blocking strength, high temperature recovery, high temperature compression set and storage modulus ratio, G′(25° C.)/G′(100° C.). Several commercially available polymers are included in the tests: Comparative G* is a substantially linear ethylene/1-octene copolymer (AFFINITY®, available from The Dow Chemical Company), Comparative H* is an elastomeric, substantially linear ethylene/1-octene copolymer (AFFINITY®EG8100, available from The Dow Chemical Company), Comparative 1 is a substantially linear ethylene/1-octene copolymer (AFFINITY®PL1840, available from The Dow Chemical Company), Comparative J is a hydrogenated styrene/butadiene/styrene triblock copolymer (KRATON™ G1652, available from KRATON Polymers), Comparative K is a thermoplastic vulcanizate (TPV, a polyolefin blend containing dispersed therein a crosslinked elastomer). Results are presented in Table 4.

TABLE 4 High Temperature Mechanical Properties Pellet 300% Blocking Strain Compression TMA-1 mm Strength Recovery Set penetration lb/ft² G'(25° C.)/ (80° C.) (70° C.) Ex. (° C.) (kPa) G'(100° C.) (percent) (percent) D* 51 — 9 Failed — E* 130 — 18 — — F* 70 141 (6.8)  9 Failed 100   5 104 0 (0)  6 81 49  6 110 — 5 — 52  7 113 — 4 84 43  8 111 — 4 Failed 41  9 97 — 4 — 66 10 108 — 5 81 55 11 100 — 8 — 68 12 88 — 8 — 79 13 95 — 6 84 71 14 125 — 7 — — 15 96 — 5 — 58 16 113 — 4 — 42 17 108 0 (0)  4 82 47 18 125 — 10 — — 19 133 — 9 — — G* 75 463 (22.2) 89 Failed 100  H* 70 213 (10.2) 29 Failed 100  I* 111 — 11 — — J* 107 — 5 Failed 100  K* 152 — 3 — 40

In Table 4, Comparative F (which is a physical blend of the two polymers resulting from simultaneous polymerizations using catalyst A1 and B1) has a 1 mm penetration temperature of about 70° C., while Examples 5-9 have a 1 mm penetration temperature of 100° C. or greater. Further, examples 10-19 all have a 1 mm penetration temperature of greater than 85° C., with most having 1 mm TMA temperature of greater than 90° C. or even greater than 100° C. This shows that the novel polymers have better dimensional stability at higher temperatures compared to a physical blend. Comparative J (a commercial SEBS) has a good 1 mm TMA temperature of about 107° C. but it has very poor (high temperature 70° C.) compression set of about 100 percent and it also failed to recover (sample broke) during a high temperature (80° C.) 300 percent strain recovery. Thus the exemplified polymers have a unique combination of properties unavailable even in some commercially available, high performance thermoplastic elastomers.

Similarly, Table 4 shows a low (good) storage modulus ratio, G′(25° C.)/G′(100° C.), for the inventive polymers of 6 or less, whereas a physical blend (Comparative F) has a storage modulus ratio of 9 and a random ethylene/octene copolymer (Comparative G) of similar density has a storage modulus ratio an order of magnitude greater (89). It is desirable that the storage modulus ratio of a polymer be as close to 1 as possible. Such polymers will be relatively unaffected by temperature, and fabricated articles made from such polymers can be usefully employed over a broad temperature range. This feature of low storage modulus ratio and temperature independence is particularly useful in elastomer applications such as in pressure sensitive adhesive formulations.

The data in Table 4 also demonstrate that the polymers of the invention possess improved pellet blocking strength. In particular, Example 5 has a pellet blocking strength of 0 MPa, meaning it is free flowing under the conditions tested, compared to Comparatives F and G which show considerable blocking. Blocking strength is important since bulk shipment of polymers having large blocking strengths can result in product clumping or sticking together upon storage or shipping, resulting in poor handling properties.

High temperature (70° C.) compression set for the inventive polymers is generally good, meaning generally less than about 80 percent, preferably less than about 70 percent and especially less than about 60 percent. In contrast, Comparatives F, G, H and J all have a 70° C. compression set of 100 percent (the maximum possible value, indicating no recovery). Good high temperature compression set (low numerical values) is especially needed for applications such as gaskets, window profiles, o-rings, and the like.

TABLE 5 Ambient Temperature Mechanical Properties Tensile Abrasion. Notched Flex Tensile Tensile Elongation Tensile Elongation Volume Tear Modulus Modulus Strength at Break¹ Strength at Break Loss Strength Ex. (MPa) (MPa) (MPa)¹ (%) (MPa) (%) (mm³) (mJ) D* 12 5 — — 10 1074 — — E* 895 589 — 31 1029 — — F* 57 46 — — 12 824 93 339  5 30 24 14 951 16 1116 48 —  6 33 29 — — 14 938 — —  7 44 37 15 846 14 854 39 —  8 41 35 13 785 14 810 45 461  9 43 38 — — 12 823 — — 10 23 23 — — 14 902 — — 11 30 26 — — 16 1090 — 976 12 20 17 12 961 13 931 — 1247  13 16 14 — — 13 814 — 691 14 212 160 — — 29 857 — — 15 18 14 12 1127  10 1573 — 2074  16 23 20 — — 12 968 — — 17 20 18 — — 13 1252 — 1274  18 323 239 — — 30 808 — — 19 706 483 — — 36 871 — — G* 15 15 — — 17 1000 — 746 H* 16 15 — — 15 829 — 569 I* 210 147 — — 29 697 — — J* — — — — 32 609 — — K* — — — — — — — — 100% Retractive Strain 300% Strain Stress Stress Recovery Recovery at 150 Compression Relaxation 21° C. 21° C. % Strain Set 21° C. at 50% Ex. (percent) (percent) (kPa) (Percent) Strain² D* 91 83 760 — — E* — — — — — F* 78 65 400 42 —  5 87 74 790 14 33  6 — 75 861 13 —  7 82 73 810 20 —  8 82 74 760 22 —  9 — — — 25 — 10 86 75 860 12 — 11 89 66 510 14 30 12 91 75 700 17 — 13 91 — — 21 — 14 — — — — — 15 89 83 770 14 — 16 88 83 1040  13 — 17 13 83 920  4 — 18 — — — — — 19 — — — — — G* 86 53 110 27 50 H* 87 60 380 23 — I* — — — — — J* 93 96 1900  25 — K* — — — 30 — ¹Tested at 51 cm/minute ²measured at 38° C. for 12 hours

Table 5 shows results for mechanical properties for the new polymers as well as for various comparison polymers at ambient temperatures. It may be seen that the inventive polymers have very good abrasion resistance when tested according to ISO 4649, generally showing a volume loss of less than about 90 mm³, preferably less than about 80 mm³, and especially less than about 50 mm³. In this test, higher numbers indicate higher volume loss and consequently lower abrasion resistance.

Tear strength as measured by tensile notched tear strength of the inventive polymers is generally 1000 mJ or higher, as shown in Table 5. Tear strength for the inventive polymers can be as high as 3000 mJ, or even as high as 5000 mJ. Comparative polymers generally have tear strengths no higher than 750 mJ.

Table 5 also shows that the polymers of the invention have better retractive stress at 150 percent strain (demonstrated by higher retractive stress values) than some of the comparative samples. Comparative Examples F, G and H have retractive stress value at 150 percent strain of 400 kPa or less, while the inventive polymers have retractive stress values at 150 percent strain of 500 kPa (Ex. 11) to as high as about 1100 kPa (Ex. 17). Polymers having higher than 150 percent retractive stress values would be quite useful for elastic applications, such as elastic fibers and fabrics, especially nonwoven fabrics. Other applications include diaper, hygiene, and medical garment waistband applications, such as tabs and elastic bands.

Table 5 also shows that stress relaxation (at 50 percent strain) is also improved (less) for the inventive polymers as compared to, for example, Comparative G. Lower stress relaxation means that the polymer retains its force better in applications such as diapers and other garments where retention of elastic properties over long time periods at body temperatures is desired.

Optical Testing

TABLE 6 Polymer Optical Properties Ex. Internal Haze (percent) Clarity (percent) 45° Gloss (percent) F* 84 22 49 G* 5 73 56 5 13 72 60 6 33 69 53 7 28 57 59 8 20 65 62 9 61 38 49 10 15 73 67 11 13 69 67 12 8 75 72 13 7 74 69 14 59 15 62 15 11 74 66 16 39 70 65 17 29 73 66 18 61 22 60 19 74 11 52 G* 5 73 56 H* 12 76 59 I* 20 75 59

The optical properties reported in Table 6 are based on compression molded films substantially lacking in orientation. Optical properties of the polymers may be varied over wide ranges, due to variation in crystallite size, resulting from variation in the quantity or chain shuttling agent employed in the polymerization.

Extraction of Multi-Block Copolymers

Extraction studies of the polymers of examples 5, 7 and Comparative E are conducted. In the experiments, the polymer sample is weighed into a glass fritted extraction thimble and fitted into a Kumagawa type extractor. The extractor with sample is purged with nitrogen, and a 500 ml, round bottom flask is charged with 350 mL of diethyl ether. The flask is then fitted to the extractor. The ether is heated while being stirred. Time is noted when the ether begins to condense into the thimble, and the extraction is allowed to proceed under nitrogen for 24 hours. At this time, heating is stopped and the solution is allowed to cool. Any ether remaining in the extractor is returned to the flask. The ether in the flask is evaporated under vacuum at ambient temperature, and the resulting solids are purged dry with nitrogen. Any residue is transferred to a weighed bottle using successive washes of hexane. The combined hexane washes are then evaporated with another nitrogen purge, and the residue dried under vacuum overnight at 40° C. Any remaining ether in the extractor is purged dry with nitrogen.

A second clean round bottom flask charged with 350 mL of hexane is then connected to the extractor. The hexane is heated to reflux with stirring and maintained at reflux for 24 hours after hexane is first noticed condensing into the thimble. Heating is then stopped and the flask is allowed to cool. Any hexane remaining in the extractor is transferred back to the flask. The hexane is removed by evaporation under vacuum at ambient temperature, and any residue remaining in the flask is transferred to a weighed bottle using successive hexane washes. The hexane in the flask is evaporated by a nitrogen purge, and the residue is vacuum dried overnight at 40° C.

The polymer sample remaining in the thimble after the extractions is transferred from the thimble to a weighed bottle and vacuum dried overnight at 40° C. Results are contained in Table 7.

TABLE 7 residue ether ether C₈ hexane C₈ C₈ wt. soluble soluble mole hexane soluble mole mole Sample (g) (g) (percent) percent¹ soluble (g) (percent) percent¹ percent¹ Comp. 1.097 0.063 5.69 12.2 0.245 22.35 13.6 6.5 F* Ex. 5 1.006 0.041 4.08 — 0.040 3.98 14.2 11.6 Ex. 7 1.092 0.017 1.59 13.3 0.012 1.10 11.7 9.9 ¹Determined by ¹³C NMR

ADDITIONAL POLYMER EXAMPLES 19A-J Continuous Solution Polymerization, Catalyst A1/B2+DEZ For Examples 19A-I

Continuous solution polymerizations are carried out in a computer controlled well-mixed reactor. Purified mixed alkanes solvent (Isopar™ E available from Exxon Mobil, Inc.), ethylene, 1-octene, and hydrogen (where used) are combined and fed to a 27 gallon reactor. The feeds to the reactor are measured by mass-flow controllers. The temperature of the feed stream is controlled by use of a glycol cooled heat exchanger before entering the reactor. The catalyst component solutions are metered using pumps and mass flow meters. The reactor is run liquid-full at approximately 550 psig pressure. Upon exiting the reactor, water and additive are injected in the polymer solution. The water hydrolyzes the catalysts, and terminates the polymerization reactions. The post reactor solution is then heated in preparation for a two-stage devolatization. The solvent and unreacted monomers are removed during the devolatization process. The polymer melt is pumped to a die for underwater pellet cutting.

For Example 19J

Continuous solution polymerizations are carried out in a computer controlled autoclave reactor equipped with an internal stirrer. Purified mixed alkanes solvent (Isopar™ E available from ExxonMobil Chemical Company), ethylene at 2.70 lbs/hour (1.22 kg/hour), 1-octene, and hydrogen (where used) are supplied to a 3.8 L reactor equipped with a jacket for temperature control and an internal thermocouple. The solvent feed to the reactor is measured by a mass-flow controller. A variable speed diaphragm pump controls the solvent flow rate and pressure to the reactor. At the discharge of the pump, a side stream is taken to provide flush flows for the catalyst and cocatalyst injection lines and the reactor agitator. These flows are measured by Micro-Motion mass flow meters and controlled by control valves or by the manual adjustment of needle valves. The remaining solvent is combined with 1-octene, ethylene, and hydrogen (where used) and fed to the reactor. A mass flow controller is used to deliver hydrogen to the reactor as needed. The temperature of the solvent/monomer solution is controlled by use of a heat exchanger before entering the reactor. This stream enters the bottom of the reactor. The catalyst component solutions are metered using pumps and mass flow meters and are combined with the catalyst flush solvent and introduced into the bottom of the reactor. The reactor is run liquid-full at 500 psig (3.45 MPa) with vigorous stirring. Product is removed through exit lines at the top of the reactor. All exit lines from the reactor are steam traced and insulated. Polymerization is stopped by the addition of a small amount of water into the exit line along with any stabilizers or other additives and passing the mixture through a static mixer. The product stream is then heated by passing through a heat exchanger before devolatilization. The polymer product is recovered by extrusion using a devolatilizing extruder and water cooled pelletizer.

Process details and results are contained in Table 8. Selected polymer properties are provided in Tables 9A-C.

In Table 9B inventive examples 19F and 19G show low immediate set of around 65-70% strain after 500% elongation.

TABLE 8 Polymerization Conditions Cat Cat Cat Cat A1² A1 B2³ B2 DEZ DEZ C₂H₄ C₈H₁₆ Solv. H₂ T Conc. Flow Conc. Flow Conc Flow Ex. lb/hr lb/hr lb/hr sccm¹ ° C. ppm lb/hr ppm lb/hr wt % lb/hr 19A 55.29 32.03 323.03 101 120 600 0.25 200 0.42 3.0 0.70 19B 53.95 28.96 325.3 577 120 600 0.25 200 0.55 3.0 0.24 19C 55.53 30.97 324.37 550 120 600 0.216 200 0.609 3.0 0.69 19D 54.83 30.58 326.33 60 120 600 0.22 200 0.63 3.0 1.39 19E 54.95 31.73 326.75 251 120 600 0.21 200 0.61 3.0 1.04 19F 50.43 34.80 330.33 124 120 600 0.20 200 0.60 3.0 0.74 19G 50.25 33.08 325.61 188 120 600 0.19 200 0.59 3.0 0.54 19H 50.15 34.87 338.17 58 120 600 0.21 200 0.66 3.0 0.70 19I 55.02 34.02 323.59 53 120 600 0.44 200 0.74 3.0 1.72 19J 7.46 9.04 50.6 47 120 150 0.22 76.7 0.36 0.5 0.19 Cocat Cocat Cocat Cocat Zn⁴ 1 1 2 2 in Poly Conc. Flow Conc. Flow polymer Rate⁵ Conv⁶ Polymer Ex. ppm lb/hr ppm lb/hr ppm lb/hr wt % wt % Ef 19A 4500 0.65 525 0.33 248 83.94 88.0 17.28 29 19B 4500 0.63 525 0.11 90 8O.72 88.1 17.2 29 19C 4500 0.61 525 0.33 246 84.13 88.9 17.16 29 19D 4500 0.66 525 0.66 491 82.56 88.1 17.07 28 19E 4500 0.64 525 0.49 368 84.11 88.4 17.43 28 19F 4500 0.52 525 0.35 257 85.31 87.5 17.09 31 19G 4500 0.51 525 0.16 194 83.72 87.5 17.34 33 19H 4500 0.52 525 0.70 259 83.21 88.0 17.46 31 19I 4500 0.70 525 1.65 600 86.63 88.0 17.6 27 19J — — — — — — — — — ¹standard cm³/min ²[N-2,6-di(1-methylethyl)phenyl)amido(2-isopropylphenyl) (α-naphthalen-2-diyl(6-pyridin-2-diyl)methane)]hafnium dimethyl ³bis-(1-(2-methylcyclohexyl)ethyl)(2-oxoyl-3,5-di(t-butyl)phenyl)immino) zirconium dimethyl ⁴ppm in final product calculated by mass balance ⁵polymer production rate ⁶weight percent ethylene conversion in reactor ⁷efficiency, kg polymer/g M where g M = g Hf + g Z

TABLE 9A Polymer Physical Properties Heat of Density Fusion Ex. (g/cc) I2 I10 I10/I2 Mw (g/mol) Mn (g/mol) Mw/Mn (J/g) 19A 0.8781 0.9 6.4 6.9 123700 61000 2.0 56 19B 0.8749 0.9 7.3 7.8 133000 44300 3.0 52 19C 0.8753 5.6 38.5 6.9 81700 37300 2.2 46 19D 0.8770 4.7 31.5 6.7 80700 39700 2.0 52 19E 0.8750 4.9 33.5 6.8 81800 41700 2.0 49 19F 0.8652 1.1 7.5 6.8 124900 60700 2.1 27 19G 0.8649 0.9 6.4 7.1 135000 64800 2.1 26 19H 0.8654 1.0 7.0 7.1 131600 66900 2.0 26 19I 0.8774 11.2 75.2 6.7 66400 33700 2.0 49 19J 0.8995 5.6 39.4 7.0 75500 29900 2.5 101 Tm- CRYSTAF TCRYSTAF TCRYSTAF Peak Area Ex. Tm (° C.) Tc (° C.) (° C.) (° C.) (wt %) 19A 119 97 46 73 40 19B 122 100 30 92 76 19C 122 100 30 92 8 19D 119 97 48 72 5 19E 121 97 36 84 12 19F 119 88 30 89 89 19G 120 92 30 90 90 19H 118 88 — — — 19I 119 99 40 79 13 19J 122 106 — — —

TABLE 9B Polymer Physical Properties of Compression Molded Film Immediate Immediate Immediate Set after Set after Set after Recovery Recovery Recovery Density Melt Index 100% Strain 300% Strain 500% Strain after 100% after 300% after 500% Example (g/cm³) (g/10 min) (%) (%) (%) (%) (%) (%) 19A 0.878 0.9 15 63 131 85 79 74 19B 0.877 0.88 14 49 97 86 84 81 19F 0.865 1 — — 70 — 87 86 19G 0.865 0.9 — — 66 — — 87 19H 0.865 0.92 — 39 — — 87 —

TABLE 9C Average Block Index For exemplary polymers¹ Example Zn/C₂ ² Average BI Polymer F 0  0 Polymer 8 0.56 0.59 Polymer 19a 1.3  0.62 Polymer 5 2.4  0.52 Polymer 19b 0.56 0.54 Polymer 19h 3.15 0.59 1. Additional information regarding the calculation of the block indices for various polymers is disclosed in U.S. patent application Ser. No. 11/376,835. entitled “Ethylene/α-Olefin Block Interpolymers”, filed on Mar. 15, 2006, in the name of Colin L. P. Shan, Lonnie Hazlitt, et. al. and assigned to Dow Global Technologies Inc., the disclose of which is incorporated by reference herein in its entirety. 2. Zn/C₂ * 1000 = (Zn feed flow*Zn concentration/1000000/Mw of Zn)/(Total Ethylene feed flow*(l-fractional ethylene conversion rate)/Mw of Ethylene)*1000. Please note that “Zn” in “Zn/C₂*1000” refers to the amount of zinc in diethyl zinc (“DEZ”) used in the polymerization process, and “C2” refers to the amount of ethylene used in the polymerization process.

EXAMPLES 20 AND 21

The ethylene/α-olefin interpolymer of Examples 20, 21, and 21A were made in a substantially similar manner as Examples 19A-I above with the polymerization conditions shown in Table 11 below. The polymers exhibited the properties shown in Tables 10 and 11 A. Tables 10 and 10A also show any additives to the polymer.

TABLE 10 Properties and Additives of Examples 20-21 Example 20 Example 21 Density (g/cc) 0.8800 0.8800 MI 1.3 1.3 Additives (ppm) DI Water 100 DI Water 75 Irgafos 168 1000 Irgafos 168 1000 Irganox 1076 250 Irganox 1076 250 Irganox 1010 200 Irganox 1010 200 Chimmasorb 100 Chimmasorb 80 2020 2020 Hard segment split 35% 35% (wt %)

TABLE 10A Properties and Additives of Example 21A Example 21A Density (g/cc) 0.88 MI 1.3 Additives (ppm) DI Water 100 Irgafos 168 1000 Irganox 1076 250 Irganox 1010 200 Chimmasorb 100 2020 Hard segment split 35% (wt %)

Irganox 1010 is Tetrakismethylene(3,5-di-t-butyl-4-hydroxyhydrocinnamate)methane. Irganox 1076 is Octadecyl-3-(3′,5′-di-t-butyl-4′-hydroxyphenyl)propionate. Irgafos 168 is Tris(2,4-di-t-butylphenyl)phosphite. Chimasorb 2020 is 1,6-Hexanediamine, N,N′-bis(2,2,6,6-tetramethyl-4-piperidinyl)-polymer with 2,3,6-trichloro-1,3,5-triazine, reaction products with, N-butyl-1-butanamine and N-butyl-2,2,6,6-tetramethyl-4-piperidinamine.

TABLE 11 Polymerization Conditions for Examples 20-21A Cat Cat Cat A1² Cat A1 B2³ B2 DEZ C₂H₄ C₈H₁₆ Solv. H₂ T Conc. Flow Conc. Flow Conc Ex. lb/br lb/hr lb/hr sccm¹ ° C. ppm lb/hr ppm lb/hr wt % 20 130.7 196.17 712.68 1767 120 499.98 1.06 299 0.57 4.8 21 132.13 199.22 708.23 1572 120 462.4 1.71 299 0.6 5.0 21A 150.9 88.6 1176 1174 120 600 2.43 100 1.66 1.5 DEZ Cocat Cocat Poly Flow Conc. Flow [C2H4]/ Rate⁵ Conv⁶ Polymer Ex. lb/hr ppm lb/hr [DEZ]⁴ lb/hr wt % wt % Eff.⁷ 20 0.48 5634 1.24 2860 177 89.3 16.9 252 21 0.47 5700 1.61 2220 183 89.2 17.5 188 21A 1.61 7500 1.52 1299 228 90.5 16.8 189 *Comparative, not an example of the invention ¹standard cm³/min ²[N-(2,6-di(1-methylethyl)phenyl)amido) (2-isopropylphenyl)(α-naphthalen-2-diyl (6-pyridin-2-diyl)methane)]hafnium dimethyl ³bis-(l-(2-methylcyclohexyl)ethyl) (2-oxoyl-3,5-di(t-butyl)phenyl)immino) zirconium dibenzyl ⁴molar ratio in reactor ⁵polymer production rate ⁶weight percent ethylene conversion in reactor ⁷efficiency, kg polymer/g M where g M = g Hf + g Z

EXAMPLE 22 Fibers of Elastic Ethylene/α-Olefin Interpolymer

The elastic ethylene/α-olefin interpolymer of Example 20 was used to make fibers. Before the fiber was made the following additives were added to the polymer: 7000 ppm PDMSO(polydimethyl siloxane), 3000 ppm CYANOX 1790 (1,3,5-tris-(4-t-butyl-3-hydroxy-),2,6-dimethylbenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione, and 3000 ppm CHIMASORB 944 Poly-[[6-(1,1,3,3-tetramethylbutyl)amino]-s-triazine-2,4-diyl][2,2,6,6-tetramethyl-4-piperidyl)imino]hexamethylene[(2,2,6,6-tetramethyl-4-piperidyl)imino]] and 0.5% by weight Tale. The fibers were produced using a die profile with rectangular 5:1 width to height ratio, a spin temperature of 270° C. a winder speed of 500 m/minute, a spin finish of 1%, a cold draw of 2%, and a spool weight of 300 g.

During the melt spinning of the fibers, a particular quench air system design was used such that there were two zones of quench air cooling, each of which was approximately 2000 mm long. The quench air flow rate was typically controlled to 0.25 m/s±10% across the chamber and up and down. The quench air temperature in both zones was maintained between 16 and 18° C. The quench air flow direction in the upper zone was from left to right while the quench air flow direction in the bottom zone was from right to left. This quench air flow arrangement minimized the amount of bowing, or deformation of the monofilament fibers in the quench chamber through a better balance of physical forces acting on the twelve individual fibers in each quench chamber. The fibers were then crosslinked using 166.4 kGy irradiation as the crosslinking agent while maintaining the temperature of the spool below about 30 C.

EXAMPLE 23 Fibers of Elastic Ethylene/α-Olefin Interpolymer

The elastic ethylene/α-olefin interpolymer of Example 20 was used to make fibers. Before the fiber was made the following additives were added to the polymer: 7000 ppm PDMSO(polydimethyl siloxane), 3000 ppm CYANOX 1790 (1,3,5-tris-(4-t-butyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione, and 3000 ppm CHIMASORB 944 Poly-[[6-(1,1,3,3-tetramethylbutyl)amino]-s-triazine-2,4-diyl][2,2,6,6-tetramethyl-4-piperidyl)imino]hexamethylene[(2,2,6,6-tetramethyl-4-piperidyl)imino]] and 0.5% by weight Talc. The fibers were produced using a die profile with rectangular 3:1 width to height ratio, a spin temperature of 270° C., a winder speed of 500 m/minute, a spin finish of 1%, a cold draw of 2%, and a spool weight of 300 g. The fibers were then crosslinked using 166.4 kGy irradiation as the crosslinking agent while maintaining the temperature of the spool below about 30 C.

EXAMPLE 24 Fibers of Blends

63.83 weight percent ENGAGE ENR7467.01 (available from The Dow Chemical Company and is an ethylene-butene copolymer having a 1.2 g/10 min melt index (190 C, 2.16 kg) and 0.862 g/cc density and contains 100 ppm Irganox 1076 and 3000 ppm talc) was blended with 34.37 weight percent AFFINITY PL1880 (available from The Dow Chemical Company and is an ethylene-octene copolymer having a 1.0 g/10 min. melt index (190 C, 2.16 kg) and 0.902 g/cc density and contains 1000 ppm Irgafos 163, 200 ppm Irganox 1010, and 250 ppm Irganox 1076), 0.7 weight percent PDMSO, 0.3 weight percent Cyanox 1790, 0.3 weight percent CH944, and 0.5 weight percent talc.

The fibers were produced using a die profile with rectangular 5:1 width to height ratio, a spin temperature of 299° C., a winder speed of 325 m/Minute, a spin finish of 1%, a cold draw of 5%, and a spool weight of 300 g. The fibers were then crosslinked using 166.4 kGy irradiation as the crosslinking agent while maintaining the temperature of the spool below about 30 C.

EXAMPLE 25 Fibers of Random Ethylene Copolymers

A random copolymer having the generic name AFFINITY™ KC8852G (available from The Dow Chemical Company) was used to make monofilament fibers of 140 denier having an approximately rectangular cross-section. AFFINITY™ KC8852G is characterized by having a melt index of 3 g/10 min., a density of 0.875 g/cm³ and similar additives as Example 21. Before the fiber was made the following additives were added to the polymer: 7000 ppm PDMSO(polydimethyl siloxane), 3000 ppm CYANOX 1790 (1,3,5-tris-(4-t-butyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione, and 3000 ppm CHIMASORB 944 Poly-[[6-(1,1,3,3-tetramethylbutyl)amino]-s-triazine-2,4-diyl][2,2,6,6-tetramethyl-4-piperidyl)imino]hexamethylene[(2,2,6,6-tetramethyl-4-piperidyl)imino]], 0.5% by weight Talc, and 0.2% by weight TiO₂. The fibers were produced using a die profile with a rectangular 3:1 width to height ratio, a spin temperature of 295° C. a winder speed of 500 m/minute, a spin finish of 1% a cold draw of 18%, and a spool weight of 300 g. The fibers were then crosslinked using 176.4 kGy irradiation as the crosslinking agent while maintaining the temperature of the spool below about 30° C.

EXAMPLE 26 Typical Heavy Weight Fabrics

The fibers of Examples 22, 23, 24, and 25 were used to make four different trial fabrics each having the following construction:

Warp yarn count: 9 Ne, 100% cotton Fill yarn count: 8.9 Ne On loom warp density: 25 On loom weft density: 18 reed width (cm): 178 cm Max wash temp 95° C. dry can 115° C. Singeing Yes @ 18 mBar/90 m/min/Tfabric max = 83° C. Softeneing + drying Yes Sanforizing Yes

The four fabrics were subjected to the tests shown in the table below. The data after 3 home launderings was used to simulate garment washing as this is a typical industry practice. Washing conditions for the 3 home launderings follow AATCC method 135-1999 and used option V for the washing conditions.

Fabric test methods include

% stretch, growth and recovery were measured according to ASTM D3107

Fabric tear strength was measured according to ASTM D1424

Fabric tensile strength, or grab strength, was measured according to ASTM D5034.

The dimensional stability was measured according to AATCC 135 with 65° C. wash temperature.

Fabric weight was measured by test method ASTM 3776.

weight after 3 Stretch home after 3 Fiber launderings width home Growth:Stretch Style type oz/yd2 % shk launderings Growth ratio Trial fabric 1 Example 22 ~13 2.4 14 4 0.3 Trial fabric 2 Example 23 ~13 2.6 12.4 3 0.2 Trial fabric 3 Example 24 ~13 3.8 14 3 0.21 Trial fabric 4 Example 25 ~13 1 8 2.8 0.4

The fabric comprising ethylene α-olefin interpolymer (trial fabric 1 and trial fabric 2) has high temperature tolerance that enables fabric to have dimensional stability, high shrinkage force at fabric finishing temperatures (50-90° C.), which allows fabrics to shrink more during finishing step, thus, fabrics have higher stretch when compared to fabrics made from standard crosslinked, homogeneously branched ethylene polymers such as XLA™. The fabric has superior chemical resistance and stability at, for example, temperatures up to 200° C.

EXAMPLE 27 Varying Amounts of Fiber Crosslinking

The elastic ethylene/α-olefin interpolymer of Example 20 was used to make monofilament fibers of 40 denier having an approximately round cross-section. Before the fiber was made the following additives were added to the polymer: 7000 ppm PDMSO(polydimethyl siloxane), 3000 ppm CYANOX 1790 (1,3,5-tris-(4-t-butyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione, and 3000 ppm CHIMASORB 944 Poly-[[6-(1,1,3,3-tetramethylbutyl)amino]-s-triazine-2,4-diyl][2,2,6,6-tetramethyl-4-piperidyl)imino]hexamethylene [(2,2,6,6-tetramethyl-4-piperidyl)imino]] and 0.5% by weight TiO₂. The fibers were produced using a die profile with circular 0.8 mm diameter, a spin temperature of 299° C. a winder speed of 650 m/minute, a spin finish of 2%, a cold draw of 6%, and a spool weight of 150 g. Fibers were then crosslinked using varying amounts of irradiation from an e-beam as the crosslinking agent.

The gel content versus the amount of irradiation is shown in FIG. 8. The gel content was determined by weighing out an approximately 25 mg fiber sample to 4 significant figure accuracy. The sample is then combined with 7 ml xylene in a capped 2-dram vial. The vial is heated 90 minutes at 125° C. to 135° C., with inversion mixing (i.e. turning vial upside down) every 15 minutes, to extract essentially all the non-crosslinked polymer. Once the vial has cooled to approximately 25° C., the xylene is decanted from the gel. The gel is rinsed in the vial with a small portion of fresh xylenes. The rinsed gel is transferred to a tared aluminum weighing pan. The tared dish with gel is vacuum dried at 125° C. for 30 minutes to remove the xylene by evaporation. The pan with dried gel is weighed on an analytical balance. The gel content is calculated based on the extracted gel weight and original fiber weight. FIG. 8 shows that as the e-beam dosage increases, the amount of crosslinking (gel content) increases. One skilled in the art will appreciate that the precise relationship between the amount of crosslinking and e-beam dosage may be affected by a given polymer's properties e.g., molecular weight or melt index.

EXAMPLE 28 Fibers of Ethylene/α-Olefin Interpolymer of Example 21A

The elastic ethylene/α-olefin interpolymer of Example 21A was used to fibers. Before the fiber was made the following additives were added to the polymer: 7000 ppm PDMSO(polydimethyl siloxane), 3000 ppm CYANOX 1790 (1,3,5-tris-(4-t-butyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione, and 3000 ppm CHIMASORB 944 Poly-[[6-(1,1,3,3-tetramethylbutyl)amino]-s-triazine-2,4-diyl][2,2,6,6-tetramethyl-4-piperidyl)imino]hexamethylene[(2,2,6,6-tetramethyl-4-piperidyl)imino]]. The fibers were produced using a round die profile of 0.8 mm diameter, a spin temperature of 280° C., a winder speed of 930 m/minute, a spin finish of 1%, and a spool weight of 365 g. The fibers were then crosslinked using 117.6 kGy irradiation as the crosslinking agent while maintaining the temperature of the spool below about 30 C.

EXAMPLE 29 Bi-Stretch Denim Fabric

A twill 3/1 bi-stretch denim fabric was made in which the warp had 100% of ring core-spun yarn. The yarn count in the warp direction was 9 Ne. The ring core-spun yarn had 100% cotton as the hard fiber sheath and the fibers of Example 28 in the core. The count for the elastic core fiber in warp was 75 denier. The weft yarn consisted of 100% polybutylene terephthalate (PBT) round, brilliant and textured fiber, type 527W by Trevira. The count for the weft yarn was 600 dTex with 128 individual filaments per yarn. The warp density on loom was 24.8 ends/cm and the weft was arranged at 16.3 picks/cm. The fabric was 179 cm wide on the loom and 171 cm wide in the greige state. After dyeing and finishing the fabric exhibited the following properties:

warp density (ASTM D93775-03): 30.8 ends/cm weft density (ASTM D3775-03): 18.1 picks/cm width (ASTM D93774-96 option b): 145 cm weight (ASTM D93776-96 option c): 390 gr/sq.m

The finished fabric was washed and dried three times according the standard ISO 6330:2000 procedure 5A, drying in tumble dryer. After the three laundering cycles the fabric exhibited the following properties:

warp density (ASTM D3775-03): 33.1 ends/cm weft density (ASTM D93775-03): 20.2 picks/cm width (ASTM D3774-96 option b): 136 cm weight (ASTM D93776-96 option c): 450 gr/sq.m warp stretch (ASTM D3107): 18% warp growth (ASTM D3107): 0.5% weft stretch (ASTM D3107): 14% weft growth (ASTM D3107): 3.9%.

EXAMPLE 30 Bi-Stretch Denim Fabric

A twill 3/1 bi-stretch denim fabric was made in which the warp and weft had 100% of ring core-spun yarn. The yarn count in warp was 9 Ne. The yarn count in weft was 10 Ne. The ring core-spun yarn had 100% of cotton as hard fiber sheath and the fibers of Example 28 in the core. The count for the elastic core fiber in warp and weft was 75 denier. The warp density on loom was 24.8 ends/cm and the weft was arranged at 17 picks/cm. The fabric was 180 cm wide on the loom and 173 cm wide in the greige state. After dyeing and finishing the fabric exhibited the following properties:

warp density (ASTM D3775-03): 28 ends/cm weft density (ASTM D3775-03): 17.9 picks/cm width (ASTM D3774-96 option b): 154 cm weight (ASTM D3776-96 option c): 303.3 gr/sq.m

The finished fabric was washed and dried three times according the standard ISO 6330:2000 procedure 2A, drying in tumble dryer. After the three laundering cycles the fabric exhibited the following properties:

warp density (ASTM D3775-03): 30 ends/cm weft density (ASTM D3775-03); 19.8 picks/cm width (ASTM D3774-96 option b): 143.2 cm weight (ASTM D3776-96 option c): 399.7 gr/sq.m warp stretch (ASTM D3107): 16.2% warp growth (ASTM D3107): 8.2% weft stretch (ASTM D3107): 18% weft growth (ASTM D3107): 8.2%. 

1. A heavy weight stretch fabric comprising one or more elastic fibers wherein the fabric has a weight of at least about 10 ounces per square yard measured according to ASTM 3776 and a stretch of at least about 10 percent measured according to ASTM D 3107 and wherein the elastic fiber comprises the reaction product of at least one ethylene/α-olefin interpolymer and at least one cross-linking agent, wherein the uncrosslinked ethylene/α-olefin interpolymer is characterized by one or more of the following characteristics: (a) has a Mw/Mn from about 1.7 to about 3.5, at least one melting point, Tm, in degrees Celsius, and a density, d, in grams/cubic centimeter, wherein the numerical values of Tm and d correspond to the relationship: T _(m)>−2002.9+4538.5(d)−2422.2(d)², or (b) has a Mw/Mn from about 1.7 to about 3.5 and is characterized by a heat of fusion, ΔH in J/g, and a delta quantity, ΔT, in degrees Celsius defined as the temperature difference between the tallest DSC peak and the tallest CRYSTAF peak, wherein the numerical values of ΔT and ΔH have the following relationships. T>−0.1299(ΔH)+62.81 for ΔH greater than zero and up to 130 J/g, T≧48° C. for ΔH greater than 130 J/g, wherein the CRYSTAF peak is determined using at least 5 percent of the cumulative polymer, and if less than 5 percent of the polymer has an identifiable CRYSTAF peak, then the CRYSTAF temperature is 30° C.; or (c) is characterized by an elastic recovery, Re, in percent at 300 percent strain and 1 cycle measured with a compression-molded film of the ethylene/α-olefin interpolymer, and has a density, d, in grams/cubic centimeter, wherein the numerical values of Re and d satisfy the following relationship when the ethylene/α-olefin interpolymer is substantially free of a cross-linked phase: Re>1481−1629(d); or (d) has a molecular fraction which elutes between 40° C. and 130° C. when fractionated using TREF, characterized in that the fraction has a molar comonomer content of at least 5 percent higher than that of a comparable random ethylene interpolymer fraction eluting between the same temperatures, wherein said comparable random ethylene interpolymer has the same comonomer(s) and a melt index, density and molar comonomer content (based on the whole polymer) within 10 percent of that of the ethylene/α-olefin interpolymer; or (e) is characterized by a storage modulus at 25° C. G′(25° C.), and a storage modulus at 100° C. G′(100° C.), wherein the ratio of G′(25° C.) to G′(100° C.) is from about 1:1 to about 10:1; or (f) at least one molecular fraction which elutes between 40° C. and 130° C. when fractionated using TREF, characterized in that the fraction has a block index of at least 0.5 and up to about 1 and a molecular weight distribution, Mw/Mn, greater than about 1.3 or (g) an average block index greater than zero and up to about 1.0 and a molecular weight distribution, Mw/Mn, greater than about 1.3.
 2. The fabric of claim 1 wherein the fabric is capable of surviving a treatment selected from the group consisting of: i) exposure to a 10% by weight sodium hypochlorite solution for a period of at least 90 minutes at a temperature of at least 140° F.; ii) exposure to a 5% by weight permanganate solution for a period of at least 90 minutes at a temperature of at least 140° F.; iii) 50 cycles of industrial laundering at temperatures of at least about 65° C.; iv) 20 cycles of drycleaning with perchloroethylene; or v) mercerization; and wherein surviving means that after said treatment the fabric exhibits a growth of less than 20% as determined according to ASTM D3107.
 3. The fabric of claim 2, wherein the fabric exhibits growth of less than about 10% as determined according to ASTM D3107 after the treatment.
 4. The fabric of claim 2 which is capable of surviving two or more of the treatments.
 5. The fabric of claim 1, wherein said fibers comprise a gel content of about 10% to about 75% by weight.
 6. The fabric of claim 1, wherein the ethylene/α-olefin interpolymer comprises from about 1 up to about 15 percent by weight of the fabric.
 7. The fabric of claim 1, wherein the fabric weighs at least about 11 ounces per square yard.
 8. The fabric of claim 1, wherein the fabric has a stretch of at least about 14 percent.
 9. The fabric of claim 1, wherein the fabric comprises at least one other material selected from the group consisting of cellulose, cotton, flax, ramie, rayon, viscose, hemp, wool, silk, linen, bamboo, tencel, mohair, polyester, polyolefin, polyamide and mixtures thereof.
 10. The fabric of claim 1, which comprises elastic fibers comprised of a polymer selected from the group consisting of polybutylene terephthalate, spandex, poly(ethylene terephthalate), poly(trimethylene terephthalate), and mixtures thereof.
 11. The fabric of claim 1, wherein the elastic fiber further comprises a polyolefin blend having an overall melt index (I₂) of less than 2.5 g/0 min before crosslinking with a density in the range of about 0.865 to 0.885 g/cm³.
 12. The fabric of claim 1, wherein the elastic fiber further comprises a polyolefin blend wherein said polyolefin blend comprises a first polyolefin having a density from about 0.855 to about 0.88 g/cm³ and a second polyolefin having a residual crystallinity at 80° C. of greater than 9%.
 13. The fabric of claim 1, wherein the elastic fiber further comprises a polyolefin blend wherein the polyolefin blend has a density from about 0.855 to about 0.88 g/cm³ or a residual crystallinity at 80° C. of greater than 9%; or both a density from about 0.855 to about 0.88 g/cm³ and a residual crystallinity at 80° C. of greater than 9%.
 14. The fabric of claim 1, wherein the elastic fiber further comprises a polyolefin blend wherein said polyolefin blend comprises a first polyolefin having a density from about 0.855 to about 0.88 g/cm³ and a second polyolefin having a residual crystallinity at 80° C. of greater than 9% and wherein the first or second polyolefin comprises homogeneously branched polyethylene.
 15. The fabric of claim 1, wherein the elastic fiber further comprises at least one other polymer.
 16. The fabric of claim 11, wherein the elastic fiber further comprises at least one other polymer and wherein the other polymer comprises an ethylene copolymer, polyethylene, propylene copolymer, polypropylene, or mixtures thereof.
 17. The fabric of claim 1, wherein the growth to stretch ratio is from about 0.05 to about 0.4.
 18. A heavy weight stretch fabric comprising an elastic fiber, wherein the fabric has a weight of at least about 10 ounces per square yard measured according to ASTM 3776 and a growth to stretch ratio of from about 0.05 to about 0.4 and wherein the elastic fiber comprises the reaction product of at least one ethylene/α-olefin interpolymer and at least one cross-linking agent, wherein the uncrosslinked ethylene/α-olefin interpolymer is characterized by one or more of the following characteristics: (a) has a Mw/Mn from about 1.7 to about 3.5, at least one melting point, Tm, in degrees Celsius, and a density, d, in grams/cubic centimeter, wherein the numerical values of Tm and d correspond to the relationship: T _(m)>−2002.9+4538.5(d)−2422.2(d)², or (b) has a Mw/Mn from about 1.7 to about 3.5, and is characterized by a heat of fusion, ΔH in J/g, and a delta quantity, ΔT, in degrees Celsius defined as the temperature difference between the tallest DSC peak and the tallest CRYSTAF peak, wherein the numerical values of ΔT and ΔH have the following relationships: T>−0.1299(ΔH)+62.81 for ΔH greater than zero and up to 130 J/g, T≧48° C. for ΔH greater than 130 J/g, wherein the CRYSTAF peak is determined using at least 5 percent of the cumulative polymer, and if less than 5 percent of the polymer has an identifiable CRYSTAF peak, then the CRYSTAF temperature is 30° C.; or (c) is characterized by an elastic recovery, Re, in percent at 300 percent strain and 1 cycle measured with a compression-molded film of the ethylene/α-olefin interpolymer, and has a density, d, in grams/cubic centimeter, wherein the numerical values of Re and d satisfy the following relationship when the ethylene/α-olefin interpolymer is substantially free of a cross-linked phase: Re>1481−1629(d); or (d) has a molecular fraction which elutes between 40° C. and 130° C. when fractionated using TREF, characterized in that the fraction has a molar comonomer content of at least 5 percent higher than that of a comparable random ethylene interpolymer fraction eluting between the same temperatures, wherein said comparable random ethylene interpolymer has the same comonomer(s) and a melt index, density, and molar comonomer content (based on the whole polymer) within 10 percent of that of the ethylene/α-olefin interpolymer; or (e) is characterized by a storage modulus at 25° C. G′(25° C.), and a storage modulus at 100° C., G′(100° C.), wherein the ratio of G′(25° C.) to G′(100° C.) is from about 1:1 to about 10:1; or (f) at least one molecular fraction which elutes between 40° C. and 130° C. when fractionated using TREF, characterized in that the fraction has a block index of at least 0.5 and up to about 1 and a molecular weight distribution, Mw/Mn, greater than about 1.3 or (g) an average block index greater than zero and up to about 1.0 and a molecular weight distribution, Mw/Mn, greater than about 1.3.
 19. The fabric of claim 18 wherein the fabric is capable of surviving a treatment selected from the group consisting of: i) exposure to a 10% by weight sodium hypochlorite solution for a period of at least 90 minutes at a temperature of at least 140° F.; ii) exposure to a 5% by weight permanganate solution for a period of at least 90 minutes at a temperature of at least 140° F.; iii) 50 cycles of industrial laundering at temperatures of at least about 65° C.; iv) 20 cycles of drycleaning with perchloroethylene; or v) mercerization; and wherein surviving means that after said treatment the fabric exhibits a growth of less than 20% as determined according to ASTM D3107.
 20. A garment made from the fabric of claim
 1. 21. A garment made from the fabric of claim 1 wherein the fabric is denim.
 22. A garment made from the fabric of claim 1 wherein the garment is a uniform.
 23. The fabric of claim 1 wherein the fabric is stone washed.
 24. The fabric of claim 1 wherein the fabric is a bi-stretch fabric.
 25. The fabric of claim 1 wherein the fabric is a bi-stretch fabric and further comprises elastic fibers comprised of a polymer selected from the group consisting of polybutylene terephthalate, spandex, poly(ethylene terephthalate), poly(trimethylene terephthalate), and mixtures thereof. 